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Network Working Group R. deBry
Request for Comments: 2566 Utah Valley State College
Category: Experimental T. Hastings
Xerox Corporation
R. Herriot
Xerox Corporation
S. Isaacson
Novell, Inc.
P. Powell
Astart Technologies
April 1999
Internet Printing Protocol/1.0: Model and Semantics
Status of this Memo
This memo defines an Experimental Protocol for the Internet
community. It does not specify an Internet standard of any kind.
Discussion and suggestions for improvement are requested.
Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (1999). All Rights Reserved.
IESG Note
This document defines an Experimental protocol for the Internet
community. The IESG expects that a revised version of this protocol
will be published as Proposed Standard protocol. The Proposed
Standard, when published, is expected to change from the protocol
defined in this memo. In particular, it is expected that the
standards-track version of the protocol will incorporate strong
authentication and privacy features, and that an "ipp:" URL type will
be defined which supports those security measures. Other changes to
the protocol are also possible. Implementors are warned that future
versions of this protocol may not interoperate with the version of
IPP defined in this document, or if they do interoperate, that some
protocol features may not be available.
The IESG encourages experimentation with this protocol, especially in
combination with Transport Layer Security (TLS) [RFC 2246], to help
determine how TLS may effectively be used as a security layer for
IPP.
deBry, et al. Experimental [Page 1]
RFC 2566 IPP/1.0: Model and Semantics April 1999
Abstract
This document is one of a set of documents, which together describe
all aspects of a new Internet Printing Protocol (IPP). IPP is an
application level protocol that can be used for distributed printing
using Internet tools and technologies. This document describes a
simplified model consisting of abstract objects, their attributes,
and their operations that is independent of encoding and transport.
The model consists of a Printer and a Job object. A Job optionally
supports multiple documents. IPP 1.0 semantics allow end-users and
operators to query printer capabilities, submit print jobs, inquire
about the status of print jobs and printers, and cancel print jobs.
This document also addresses security, internationalization, and
directory issues.
The full set of IPP documents includes:
Design Goals for an Internet Printing Protocol [RFC2567]
Rationale for the Structure and Model and Protocol for the Internet
Printing Protocol [RFC2568]
Internet Printing Protocol/1.0: Model and Semantics (this document)
Internet Printing Protocol/1.0: Encoding and Transport [RFC2565]
Internet Printing Protocol/1.0: Implementer's Guide [ipp-iig]
Mapping between LPD and IPP Protocols [RFC2569]
The "Design Goals for an Internet Printing Protocol" document takes a
broad look at distributed printing functionality, and it enumerates
real-life scenarios that help to clarify the features that need to be
included in a printing protocol for the Internet. It identifies
requirements for three types of users: end users, operators, and
administrators. It calls out a subset of end user requirements that
are satisfied in IPP/1.0. Operator and administrator requirements
are out of scope for version 1.0.
The "Rationale for the Structure and Model and Protocol for the
Internet Printing Protocol" document describes IPP from a high level
view, defines a roadmap for the various documents that form the suite
of IPP specifications, and gives background and rationale for the
IETF working group's major decisions.
The "Internet Printing Protocol/1.0: Encoding and Transport" document
is a formal mapping of the abstract operations and attributes defined
in the model document onto HTTP/1.1. It defines the encoding rules
for a new Internet media type called "application/ipp".
The "Internet Printing Protocol/1.0: Implementer's Guide" document
gives insight and advice to implementers of IPP clients and IPP
objects. It is intended to help them understand IPP/1.0 and some of
deBry, et al. Experimental [Page 2]
RFC 2566 IPP/1.0: Model and Semantics April 1999
the considerations that may assist them in the design of their client
and/or IPP object implementations. For example, a typical order of
processing requests is given, including error checking. Motivation
for some of the specification decisions is also included.
The "Mapping between LPD and IPP Protocols" document gives some
advice to implementers of gateways between IPP and LPD (Line Printer
Daemon) implementations.
Table of Contents
1. Introduction 8
1.1 Simplified Printing Model 9
2. IPP Objects 11
2.1 Printer Object 12
2.2 Job Object 14
2.3 Object Relationships 14
2.4 Object Identity 15
3. IPP Operations 18
3.1 Common Semantics 19
3.1.1 Required Parameters 19
3.1.2 Operation IDs and Request IDs 20
3.1.3 Attributes 20
3.1.4 Character Set and Natural Language Operation Attributes 22
3.1.4.1 Request Operation Attributes 22
3.1.4.2 Response Operation Attributes 26
3.1.5 Operation Targets 28
3.1.6 Operation Status Codes and Messages 29
3.1.7 Versions 30
3.1.8 Job Creation Operations 32
3.2 Printer Operations 34
3.2.1 Print-Job Operation 34
3.2.1.1 Print-Job Request 34
3.2.1.2 Print-Job Response 38
3.2.2 Print-URI Operation 41
3.2.3 Validate-Job Operation 42
3.2.4 Create-Job Operation 42
3.2.5 Get-Printer-Attributes Operation 43
3.2.5.1 Get-Printer-Attributes Request 44
3.2.5.2 Get-Printer-Attributes Response 46
3.2.6 Get-Jobs Operation 47
3.2.6.1 Get-Jobs Request 47
3.2.6.2 Get-Jobs Response 49
3.3 Job Operations 50
3.3.1 Send-Document Operation 50
3.3.1.1 Send-Document Request 51
3.3.1.2 Send-Document Response 53
3.3.2 Send-URI Operation 54
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3.3.3 Cancel-Job Operation 54
3.3.3.1 Cancel-Job Request 54
3.3.3.2 Cancel-Job Response 55
3.3.4 Get-Job-Attributes Operation 56
3.3.4.1 Get-Job-Attributes Request 57
3.3.4.2 Get-Job-Attributes Response 57
4. Object Attributes 58
4.1 Attribute Syntaxes 59
4.1.1 'text' 60
4.1.1.1 'textWithoutLanguage' 61
4.1.1.2 'textWithLanguage' 61
4.1.2 'name' 62
4.1.2.1 'nameWithoutLanguage' 62
4.1.2.2 'nameWithLanguage' 63
4.1.2.3 Matching 'name' attribute values 63
4.1.3 'keyword' 64
4.1.4 'enum' 65
4.1.5 'uri' 65
4.1.6 'uriScheme' 65
4.1.7 'charset' 66
4.1.8 'naturalLanguage' 67
4.1.9 'mimeMediaType' 67
4.1.10 'octetString' 69
4.1.11 'boolean' 69
4.1.12 'integer' 69
4.1.13 'rangeOfInteger' 69
4.1.14 'dateTime' 69
4.1.15 'resolution' 69
4.1.16 '1setOf X' 70
4.2 Job Template Attributes 70
4.2.1 job-priority (integer(1:100)) 74
4.2.2 job-hold-until (type3 keyword | name (MAX)) 75
4.2.3 job-sheets (type3 keyword | name(MAX)) 75
4.2.4 multiple-document-handling (type2 keyword) 76
4.2.5 copies (integer(1:MAX)) 77
4.2.6 finishings (1setOf type2 enum) 78
4.2.7 page-ranges (1setOf rangeOfInteger (1:MAX)) 79
4.2.8 sides (type2 keyword) 80
4.2.9 number-up (integer(1:MAX)) 80
4.2.10 orientation-requested (type2 enum) 81
4.2.11 media (type3 keyword | name(MAX)) 82
4.2.12 printer-resolution (resolution) 83
4.2.13 print-quality (type2 enum) 83
4.3 Job Description Attributes 84
4.3.1 job-uri (uri) 85
4.3.2 job-id (integer(1:MAX)) 85
4.3.3 job-printer-uri (uri) 86
4.3.4 job-more-info (uri) 86
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4.3.5 job-name (name(MAX)) 86
4.3.6 job-originating-user-name (name(MAX)) 86
4.3.7 job-state (type1 enum) 87
4.3.8 job-state-reasons (1setOf type2 keyword) 90
4.3.9 job-state-message (text(MAX)) 92
4.3.10 number-of-documents (integer(0:MAX)) 93
4.3.11 output-device-assigned (name(127)) 93
4.3.12 time-at-creation (integer(0:MAX)) 93
4.3.13 time-at-processing (integer(0:MAX)) 93
4.3.14 time-at-completed (integer(0:MAX)) 94
4.3.15 number-of-intervening-jobs (integer(0:MAX)) 94
4.3.16 job-message-from-operator (text(127)) 94
4.3.17 job-k-octets (integer(0:MAX)) 94
4.3.18 job-impressions (integer(0:MAX)) 95
4.3.19 job-media-sheets (integer(0:MAX)) 95
4.3.20 job-k-octets-processed (integer(0:MAX)) 96
4.3.21 job-impressions-completed (integer(0:MAX)) 96
4.3.22 job-media-sheets-completed (integer(0:MAX)) 96
4.3.23 attributes-charset (charset) 97
4.3.24 attributes-natural-language (naturalLanguage) 97
4.4 Printer Description Attributes 97
4.4.1 printer-uri-supported (1setOf uri) 99
4.4.2 uri-security-supported (1setOf type2 keyword) 100
4.4.3 printer-name (name(127)) 101
4.4.4 printer-location (text(127)) 101
4.4.5 printer-info (text(127)) 101
4.4.6 printer-more-info (uri) 101
4.4.7 printer-driver-installer (uri) 102
4.4.8 printer-make-and-model (text(127)) 102
4.4.9 printer-more-info-manufacturer (uri) 102
4.4.10 printer-state (type1 enum) 102
4.4.11 printer-state-reasons (1setOf type2 keyword) 103
4.4.12 printer-state-message (text(MAX)) 106
4.4.13 operations-supported (1setOf type2 enum) 106
4.4.14 charset-configured (charset) 107
4.4.15 charset-supported (1setOf charset) 107
4.4.16 natural-language-configured (naturalLanguage) 107
4.4.17 generated-natural-language-supported(1setOf naturalLanguage108
4.4.18 document-format-default (mimeMediaType) 108
4.4.19 document-format-supported (1setOf mimeMediaType) 108
4.4.20 printer-is-accepting-jobs (boolean) 109
4.4.21 queued-job-count (integer(0:MAX)) 109
4.4.22 printer-message-from-operator (text(127)) 109
4.4.23 color-supported (boolean) 109
4.4.24 reference-uri-schemes-supported (1setOf uriScheme) 109
4.4.25 pdl-override-supported (type2 keyword) 110
4.4.26 printer-up-time (integer(1:MAX)) 110
4.4.27 printer-current-time (dateTime) 111
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4.4.28 multiple-operation-time-out (integer(1:MAX)) 111
4.4.29 compression-supported (1setOf type3 keyword) 111
4.4.30 job-k-octets-supported (rangeOfInteger(0:MAX)) 112
4.4.31 job-impressions-supported (rangeOfInteger(0:MAX)) 112
4.4.32 job-media-sheets-supported (rangeOfInteger(0:MAX)) 112
5. Conformance 112
5.1 Client Conformance Requirements 112
5.2 IPP Object Conformance Requirements 113
5.2.1 Objects 113
5.2.2 Operations 113
5.2.3 IPP Object Attributes 114
5.2.4 Extensions 114
5.2.5 Attribute Syntaxes 115
5.3 Charset and Natural Language Requirements 115
5.4 Security Conformance Requirements 115
6. IANA Considerations (registered and private extensions) 116
6.1 Typed 'keyword' and 'enum' Extensions 116
6.2 Attribute Extensibility 119
6.3 Attribute Syntax Extensibility 119
6.4 Operation Extensibility 120
6.5 Attribute Groups 120
6.6 Status Code Extensibility 120
6.7 Registration of MIME types/sub-types for document-formats 121
6.8 Registration of charsets for use in 'charset' attribute values121
7. Internationalization Considerations 121
8. Security Considerations 125
8.1 Security Scenarios 126
8.1.1 Client and Server in the Same Security Domain 126
8.1.2 Client and Server in Different Security Domains 126
8.1.3 Print by Reference 127
8.2 URIs for SSL3 and non-SSL3 Access 127
8.3 The "requesting-user-name" (name(MAX)) Operation Attribute 127
8.4 Restricted Queries 129
8.5 Queries on jobs submitted using non-IPP protocols 129
8.6 IPP Security Application Profile for SSL3 130
9. References 131
10. Authors' Addresses 134
11. Formats for IPP Registration Proposals 136
11.1 Type2 keyword attribute values registration 136
11.2 Type3 keyword attribute values registration 137
11.3 Type2 enum attribute values registration 137
11.4 Type3 enum attribute values registration 137
11.5 Attribute registration 138
11.6 Attribute Syntax registration 138
11.7 Operation registration 139
11.8 Attribute Group registration 139
11.9 Status code registration 139
12.APPENDIX A: Terminology 141
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12.1 Conformance Terminology 141
12.1.1 NEED NOT 141
12.2 Model Terminology 141
12.2.1 Keyword 141
12.2.2 Attributes 141
12.2.2.1 Attribute Name 141
12.2.2.2 Attribute Group Name 142
12.2.2.3 Attribute Value 142
12.2.2.4 Attribute Syntax 142
12.2.3 Supports 142
12.2.4 print-stream page 144
12.2.5 impression 144
13.APPENDIX B: Status Codes and Suggested Status Code Messages 145
13.1 Status Codes 146
13.1.1 Informational 146
13.1.2 Successful Status Codes 146
13.1.2.1 successful-ok (0x0000) 146
13.1.2.2 successful-ok-ignored-or-substituted-attributes (0x0001) 146
13.1.2.3 successful-ok-conflicting-attributes (0x0002) 147
13.1.3 Redirection Status Codes 147
13.1.4 Client Error Status Codes 147
13.1.4.1 client-error-bad-request (0x0400) 147
13.1.4.2 client-error-forbidden (0x0401) 147
13.1.4.3 client-error-not-authenticated (0x0402) 148
13.1.4.4 client-error-not-authorized (0x0403) 148
13.1.4.5 client-error-not-possible (0x0404) 148
13.1.4.6 client-error-timeout (0x0405) 148
13.1.4.7 client-error-not-found (0x0406) 149
13.1.4.8 client-error-gone (0x0407) 149
13.1.4.9 client-error-request-entity-too-large (0x0408) 149
13.1.4.10client-error-request-value-too-long (0x0409) 150
13.1.4.11client-error-document-format-not-supported (0x040A) 150
13.1.4.12client-error-attributes-or-values-not-supported (0x040B) 150
13.1.4.13client-error-uri-scheme-not-supported (0x040C) 151
13.1.4.14client-error-charset-not-supported (0x040D) 151
13.1.4.15client-error-conflicting-attributes (0x040E) 151
13.1.5 Server Error Status Codes 151
13.1.5.1 server-error-internal-error (0x0500) 151
13.1.5.2 server-error-operation-not-supported (0x0501) 152
13.1.5.3 server-error-service-unavailable (0x0502) 152
13.1.5.4 server-error-version-not-supported (0x0503) 152
13.1.5.5 server-error-device-error (0x0504) 152
13.1.5.6 server-error-temporary-error (0x0505) 153
13.1.5.7 server-error-not-accepting-jobs (0x0506) 153
13.1.5.8 server-error-busy (0x0507) 153
13.1.5.9 server-error-job-canceled (0x0508) 153
13.2 Status Codes for IPP Operations 153
14.APPENDIX C: "media" keyword values 155
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15.APPENDIX D: Processing IPP Attributes 160
15.1 Fidelity 160
15.2 Page Description Language (PDL) Override 161
15.3 Using Job Template Attributes During Document Processing. 163
16.APPENDIX E: Generic Directory Schema 166
17.APPENDIX F: Change History for the Model and Semantics document 168
18.FULL COPYRIGHT STATEMENT 173
1. Introduction
The Internet Printing Protocol (IPP) is an application level protocol
that can be used for distributed printing using Internet tools and
technologies. IPP version 1.0 (IPP/1.0) focuses only on end user
functionality. This document is just one of a suite of documents
that fully define IPP. The full set of IPP documents includes:
Design Goals for an Internet Printing Protocol [RFC2567]
Rationale for the Structure and Model and Protocol for the Internet
Printing Protocol [RFC2568]
Internet Printing Protocol/1.0: Model and Semantics (this document)
Internet Printing Protocol/1.0: Encoding and Transport [RFC2565]
Internet Printing Protocol/1.0: Implementer's Guide [ipp-iig]
Mapping between LPD and IPP Protocols [RFC2569]
Anyone reading these documents for the first time is strongly
encouraged to read the IPP documents in the above order.
This document is laid out as follows:
- The rest of Section 1 is an introduction to the IPP simplified
model for distributed printing.
- Section 2 introduces the object types covered in the model with
their basic behaviors, attributes, and interactions.
- Section 3 defines the operations included in IPP/1.0. IPP
operations are synchronous, therefore, for each operation, there
is a both request and a response.
- Section 4 defines the attributes (and their syntaxes) that are
used in the model.
- Sections 5 - 6 summarizes the implementation conformance
requirements for objects that support the protocol and IANA
considerations, respectively.
- Sections 7 - 11 cover the Internationalization and Security
considerations as well as References, Author contact information,
and Formats for Registration Proposals.
- Sections 12 - 14 are appendices that cover Terminology, Status
Codes and Messages, and "media" keyword values.
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RFC 2566 IPP/1.0: Model and Semantics April 1999
Note: This document uses terms such as "attributes",
"keywords", and "support". These terms have special
meaning and are defined in the model terminology section
12.2. Capitalized terms, such as MUST, MUST NOT, REQUIRED,
SHOULD, SHOULD NOT, MAY, NEED NOT, and OPTIONAL, have
special meaning relating to conformance. These terms are
defined in section 12.1 on conformance terminology, most of
which is taken from RFC 2119 [RFC2119].
- Section 15 is an appendix that helps to clarify the effects of
interactions between related attributes and their values.
- Section 16 is an appendix that enumerates the subset of Printer
attributes that form a generic directory schema. These
attributes are useful when registering a Printer so that a
client can find the Printer not just by name, but by filtered
searches as well.
- Section 17 is an appendix that provides a Change History
summarizing the clarification and changes that might affect an
implementation since the June 30, 1998 draft.
1.1 Simplified Printing Model
In order to achieve its goal of realizing a workable printing
protocol for the Internet, the Internet Printing Protocol (IPP) is
based on a simplified printing model that abstracts the many
components of real world printing solutions. The Internet is a
distributed computing environment where requesters of print services
(clients, applications, printer drivers, etc.) cooperate and interact
with print service providers. This model and semantics document
describes a simple, abstract model for IPP even though the underlying
configurations may be complex "n-tier" client/server systems. An
important simplifying step in the IPP model is to expose only the key
objects and interfaces required for printing. The model described in
this model document does not include features, interfaces, and
relationships that are beyond the scope of the first version of IPP
(IPP/1.0). IPP/1.0 incorporates many of the relevant ideas and
lessons learned from other specification and development efforts
[HTPP] [ISO10175] [LDPA] [P1387.4] [PSIS] [RFC1179] [SWP]. IPP is
heavily influenced by the printing model introduced in the Document
Printing Application (DPA) [ISO10175] standard. Although DPA
specifies both end user and administrative features, IPP version 1.0
(IPP/1.0) focuses only on end user functionality.
The IPP/1.0 model encapsulates the important components of
distributed printing into two object types:
- Printer (Section 2.1)
- Job (Section 2.2)
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Each object type has an associated set of operations (see section 3)
and attributes (see section 4).
It is important, however, to understand that in real system
implementations (which lie underneath the abstracted IPP/1.0 model),
there are other components of a print service which are not
explicitly defined in the IPP/1.0 model. The following figure
illustrates where IPP/1.0 fits with respect to these other
components.
+--------------+
| Application |
o +. . . . . . . |
\|/ | Spooler |
/ \ +. . . . . . . | +---------+
End-User | Print Driver |---| File |
+-----------+ +-----+ +------+-------+ +----+----+
| Browser | | GUI | | |
+-----+-----+ +--+--+ | |
| | | |
| +---+------------+---+ |
N D S | | IPP Client |------------+
O I E | +---------+----------+
T R C | |
I E U |
F C R -------------- Transport ------------------
I T I
C O T | --+
A R Y +--------+--------+ |
T Y | IPP Server | |
I +--------+--------+ |
O | |
N +-----------------+ | IPP Printer
| Print Service | |
+-----------------+ |
| --+
+-----------------+
| Output Device(s)|
+-----------------+
An IPP Printer object encapsulates the functions normally associated
with physical output devices along with the spooling, scheduling and
multiple device management functions often associated with a print
server. Printer objects are optionally registered as entries in a
directory where end users find and select them based on some sort of
filtered and context based searching mechanism (see section 16). The
directory is used to store relatively static information about the
Printer, allowing end users to search for and find Printers that
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match their search criteria, for example: name, context, printer
capabilities, etc. The more dynamic information, such as state,
currently loaded and ready media, number of jobs at the Printer,
errors, warnings, and so forth, is directly associated with the
Printer object itself rather than with the entry in the directory
which only represents the Printer object.
IPP clients implement the IPP protocol on the client side and give
end users (or programs running on behalf of end users) the ability to
query Printer objects and submit and manage print jobs. An IPP
server is just that part of the Printer object that implements the
server-side protocol. The rest of the Printer object implements (or
gateways into) the application semantics of the print service itself.
The Printer objects may be embedded in an output device or may be
implemented on a host on the network that communicates with an output
device.
When a job is submitted to the Printer object and the Printer object
validates the attributes in the submission request, the Printer
object creates a new Job object. The end user then interacts with
this new Job object to query its status and monitor the progress of
the job. End users may also cancel the print job by using the Job
object's Cancel-Job operation. The notification service is out of
scope for IPP/1.0, but using such a notification service, the end
user is able to register for and receive Printer specific and Job
specific events. An end user can query the status of Printer objects
and can follow the progress of Job objects by polling using the Get-
Printer-Attributes, Get-Jobs, and Get-Job-Attributes operations.
2. IPP Objects
The IPP/1.0 model introduces objects of type Printer and Job. Each
type of object models relevant aspects of a real-world entity such as
a real printer or real print job. Each object type is defined as a
set of possible attributes that may be supported by instances of that
object type. For each object (instance), the actual set of supported
attributes and values describe a specific implementation. The
object's attributes and values describe its state, capabilities,
realizable features, job processing functions, and default behaviors
and characteristics. For example, the Printer object type is defined
as a set of attributes that each Printer object potentially supports.
In the same manner, the Job object type is defined as a set of
attributes that are potentially supported by each Job object.
Each attribute included in the set of attributes defining an object
type is labeled as:
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- "REQUIRED": each object MUST support the attribute.
- "OPTIONAL": each object MAY support the attribute.
There is no such similar labeling of attribute values. However, if
an implementation supports an attribute, it MUST support at least one
of the possible values for that attribute.
2.1 Printer Object
The major component of the IPP/1.0 model is the Printer object. A
Printer object implements the server-side of the IPP/1.0 protocol.
Using the protocol, end users may query the attributes of the Printer
object and submit print jobs to the Printer object. The actual
implementation components behind the Printer abstraction may take on
different forms and different configurations. However, the model
abstraction allows the details of the configuration of real
components to remain opaque to the end user. Section 3 describes
each of the Printer operations in detail.
The capabilities and state of a Printer object are described by its
attributes. Printer attributes are divided into two groups:
- "job-template" attributes: These attributes describe supported
job processing capabilities and defaults for the Printer object.
(See section 4.2)
- "printer-description" attributes: These attributes describe the
Printer object's identification, state, location, references to
other sources of information about the Printer object, etc. (see
section 4.4)
Since a Printer object is an abstraction of a generic document output
device and print service provider, a Printer object could be used to
represent any real or virtual device with semantics consistent with
the Printer object, such as a fax device, an imager, or even a CD
writer.
Some examples of configurations supporting a Printer object include:
1) An output device with no spooling capabilities
2) An output device with a built-in spooler
3) A print server supporting IPP with one or more associated output
devices
3a) The associated output devices may or may not be capable of
spooling jobs
3b) The associated output devices may or may not support IPP
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RFC 2566 IPP/1.0: Model and Semantics April 1999
The following figures show some examples of how Printer objects can
be realized on top of various distributed printing configurations.
The embedded case below represents configurations 1 and 2. The hosted
and fan-out figures below represent configurations 3a and 3b.
Legend:
##### indicates a Printer object which is
either embedded in an output device or is
hosted in a server. The Printer object
might or might not be capable of queuing/spooling.
any indicates any network protocol or direct
connect, including IPP
embedded printer:
output device
+---------------+
O +--------+ | ########### |
/|\ | client |------------IPP------------># Printer # |
/ \ +--------+ | # Object # |
| ########### |
+---------------+
hosted printer:
+---------------+
O +--------+ ########### | |
/|\ | client |--IPP--># Printer #-any->| output device |
/ \ +--------+ # Object # | |
########### +---------------+
+---------------+
fan out: | |
+-->| output device |
any/ | |
O +--------+ ########### / +---------------+
/|\ | client |-IPP-># Printer #--*
/ \ +--------+ # Object # \ +---------------+
########### any\ | |
+-->| output device |
| |
+---------------+
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2.2 Job Object
A Job object is used to model a print job. A Job object contains
documents. The information required to create a Job object is sent
in a create request from the end user via an IPP Client to the
Printer object. The Printer object validates the create request, and
if the Printer object accepts the request, the Printer object creates
the new Job object. Section 3 describes each of the Job operations
in detail.
The characteristics and state of a Job object are described by its
attributes. Job attributes are grouped into two groups as follows:
- "job-template" attributes: These attributes can be supplied by
the client or end user and include job processing instructions
which are intended to override any Printer object defaults and/or
instructions embedded within the document data. (See section 4.2)
- "job-description" attributes: These attributes describe the Job
object's identification, state, size, etc. The client supplies
some of these attributes, and the Printer object generates others.
(See section 4.3)
An implementation MUST support at least one document per Job object.
An implementation MAY support multiple documents per Job object. A
document is either:
- a stream of document data in a format supported by the Printer
object (typically a Page Description Language - PDL), or
- a reference to such a stream of document data
In IPP/1.0, a document is not modeled as an IPP object, therefore it
has no object identifier or associated attributes. All job
processing instructions are modeled as Job object attributes. These
attributes are called Job Template attributes and they apply equally
to all documents within a Job object.
2.3 Object Relationships
IPP objects have relationships that are maintained persistently along
with the persistent storage of the object attributes.
A Printer object can represent either one or more physical output
devices or a logical device which "processes" jobs but never actually
uses a physical output device to put marks on paper. Examples of
logical devices include a Web page publisher or a gateway into an
online document archive or repository. A Printer object contains
zero or more Job objects.
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A Job object is contained by exactly one Printer object, however the
identical document data associated with a Job object could be sent to
either the same or a different Printer object. In this case, a
second Job object would be created which would be almost identical to
the first Job object, however it would have new (different) Job
object identifiers (see section 2.4).
A Job object is either empty (before any documents have been added)
or contains one or more documents. If the contained document is a
stream of document data, that stream can be contained in only one
document. However, there can be identical copies of the stream in
other documents in the same or different Job objects. If the
contained document is just a reference to a stream of document data,
other documents (in the same or different Job object(s)) may contain
the same reference.
2.4 Object Identity
All Printer and Job objects are identified by a Uniform Resource
Identifier (URI) [RFC2396] so that they can be persistently and
unambiguously referenced. The notion of a URI is a useful concept,
however, until the notion of URI is more stable (i.e., defined more
completely and deployed more widely), it is expected that the URIs
used for IPP objects will actually be URLs [RFC2396]. Since every
URL is a specialized form of a URI, even though the more generic term
URI is used throughout the rest of this document, its usage is
intended to cover the more specific notion of URL as well.
An administrator configures Printer objects to either support or not
support authentication and/or message privacy using SSL3 [SSL] (the
mechanism for security configuration is outside the scope of
IPP/1.0). In some situations, both types of connections (both
authenticated and unauthenticated) can be established using a single
communication channel that has some sort of negotiation mechanism.
In other situations, multiple communication channels are used, one
for each type of security configuration. Section 8 provides a full
description of all security considerations and configurations.
If a Printer object supports more than one communication channel,
some or all of those channels might support and/or require different
security mechanisms. In such cases, an administrator could expose
the simultaneous support for these multiple communication channels as
multiple URIs for a single Printer object where each URI represents
one of the communication channels to the Printer object. To support
this flexibility, the IPP Printer object type defines a multi-valued
identification attribute called the "printer-uri-supported"
attribute. It MUST contain at least one URI. It MAY contain more
than one URI. That is, every Printer object will have at least one
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URI that identifies at least one communication channel to the Printer
object, but it may have more than one URI where each URI identifies a
different communication channel to the Printer object. The
"printer-uri-supported" attribute has a companion attribute, the
"uri-security-supported" attribute, that has the same cardinality as
"printer-uri-supported". The purpose of the "uri-security-supported"
attribute is to indicate the security mechanisms (if any) used for
each URI listed in "printer-uri-supported". These two attributes are
fully described in sections 4.4.1 and 4.4.2.
When a job is submitted to the Printer object via a create request,
the client supplies only a single Printer object URI. The client
supplied Printer object URI MUST be one of the values in the
"printer-uri-supported" Printer attribute.
Note: IPP/1.0 does not specify how the client obtains the client
supplied URI, but it is RECOMMENDED that a Printer object be
registered as an entry in a directory service. End-users and
programs can then interrogate the directory searching for Printers.
Section 16 defines a generic schema for Printer object entries in the
directory service and describes how the entry acts as a bridge to the
actual IPP Printer object. The entry in the directory that
represents the IPP Printer object includes the possibly many URIs for
that Printer object as values in one its attributes.
When a client submits a create request to the Printer object, the
Printer object validates the request and creates a new Job object.
The Printer object assigns the new Job object a URI which is stored
in the "job-uri" Job attribute. This URI is then used by clients as
the target for subsequent Job operations. The Printer object
generates a Job URI based on its configured security policy and the
URI used by the client in the create request.
For example, consider a Printer object that supports both a
communication channel secured by the use of SSL3 (using HTTP over
SSL3 with an "https" schemed URI) and another open communication
channel that is not secured with SSL3 (using a simple "http" schemed
URI). If a client were to submit a job using the secure URI, the
Printer object would assign the new Job object a secure URI as well.
If a client were to submit a job using the open-channel URI, the
Printer would assign the new Job object an open-channel URI.
In addition, the Printer object also populates the Job object's
"job-printer-uri" attribute. This is a reference back to the Printer
object that created the Job object. If a client only has access to a
Job object's "job-uri" identifier, the client can query the Job's
"job-printer-uri" attribute in order to determine which Printer
object created the Job object. If the Printer object supports more
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than one URI, the Printer object picks the one URI supplied by the
client when creating the job to build the value for and to populate
the Job's "job-printer-uri" attribute.
Allowing Job objects to have URIs allows for flexibility and
scalability. For example, in some implementations, the Printer
object might create Jobs that are processed in the same local
environment as the Printer object itself. In this case, the Job URI
might just be a composition of the Printer's URI and some unique
component for the Job object, such as the unique 32-bit positive
integer mentioned later in this paragraph. In other implementations,
the Printer object might be a central clearing-house for validating
all Job object creation requests, but the Job object itself might be
created in some environment that is remote from the Printer object.
In this case, the Job object's URI may have no physical-location
relationship at all to the Printer object's URI. Again, the fact
that Job objects have URIs allows for flexibility and scalability,
however, many existing printing systems have local models or
interface constraints that force print jobs to be identified using
only a 32-bit positive integer rather than an independent URI. This
numeric Job ID is only unique within the context of the Printer
object to which the create request was originally submitted.
Therefore, in order to allow both types of client access to IPP Job
objects (either by Job URI or by numeric Job ID), when the Printer
object successfully processes a create request and creates a new Job
object, the Printer object MUST generate both a Job URI and a Job ID.
The Job ID (stored in the "job-id" attribute) only has meaning in the
context of the Printer object to which the create request was
originally submitted. This requirement to support both Job URIs and
Job IDs allows all types of clients to access Printer objects and Job
objects no matter the local constraints imposed on the client
implementation.
In addition to identifiers, Printer objects and Job objects have
names ("printer-name" and "job-name"). An object name NEED NOT be
unique across all instances of all objects. A Printer object's name
is chosen and set by an administrator through some mechanism outside
the scope of IPP/1.0. A Job object's name is optionally chosen and
supplied by the IPP client submitting the job. If the client does
not supply a Job object name, the Printer object generates a name for
the new Job object. In all cases, the name only has local meaning.
To summarize:
- Each Printer object is identified with one or more URIs. The
Printer's "printer-uri-supported" attribute contains the URI(s).
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- The Printer object's "uri-security-supported" attribute
identifies the communication channel security protocols that may
or may not have been configured for the various Printer object
URIs (e.g., 'ssl3' or 'none').
- Each Job object is identified with a Job URI. The Job's "job-uri"
attribute contains the URI.
- Each Job object is also identified with Job ID which is a 32-bit,
positive integer. The Job's "job-id" attribute contains the Job
ID. The Job ID is only unique within the context of the Printer
object which created the Job object.
- Each Job object has a "job-printer-uri" attribute which contains
the URI of the Printer object that was used to create the Job
object. This attribute is used to determine the Printer object
that created a Job object when given only the URI for the Job
object. This linkage is necessary to determine the languages,
charsets, and operations which are supported on that Job (the
basis for such support comes from the creating Printer object).
- Each Printer object has a name (which is not necessarily unique).
The administrator chooses and sets this name through some
mechanism outside the scope of IPP/1.0 itself. The Printer
object's "printer-name" attribute contains the name.
- Each Job object has a name (which is not necessarily unique). The
client optionally supplies this name in the create request. If
the client does not supply this name, the Printer object generates
a name for the Job object. The Job object's "job-name" attribute
contains the name.
3. IPP Operations
IPP objects support operations. An operation consists of a request
and a response. When a client communicates with an IPP object, the
client issues an operation request to the URI for that object.
Operation requests and responses have parameters that identify the
operation. Operations also have attributes that affect the run-time
characteristics of the operation (the intended target, localization
information, etc.). These operation-specific attributes are called
operation attributes (as compared to object attributes such as
Printer object attributes or Job object attributes). Each request
carries along with it any operation attributes, object attributes,
and/or document data required to perform the operation. Each request
requires a response from the object. Each response indicates success
or failure of the operation with a status code as a response
parameter. The response contains any operation attributes, object
attributes, and/or status messages generated during the execution of
the operation request.
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This section describes the semantics of the IPP operations, both
requests and responses, in terms of the parameters, attributes, and
other data associated with each operation.
The IPP/1.0 Printer operations are:
Print-Job (section 3.2.1)
Print-URI (section 3.2.2)
Validate-Job (section 3.2.3)
Create-Job (section 3.2.4)
Get-Printer-Attributes (section 3.2.5)
Get-Jobs (section 3.2.6)
The Job operations are:
Send-Document (section 3.3.1)
Send-URI (section 3.3.2)
Cancel-Job (section 3.3.3)
Get-Job-Attributes (section 3.3.4)
The Send-Document and Send-URI Job operations are used to add a new
document to an existing multi-document Job object created using the
Create-Job operation.
3.1 Common Semantics
All IPP operations require some common parameters and operation
attributes. These common elements and their semantic characteristics
are defined and described in more detail in the following sections.
3.1.1 Required Parameters
Every operation request contains the following REQUIRED parameters:
- a "version-number",
- an "operation-id",
- a "request-id", and
- the attributes that are REQUIRED for that type of request.
Every operation response contains the following REQUIRED parameters:
- a "version-number",
- a "status-code",
- the "request-id" that was supplied in the corresponding request,
and
- the attributes that are REQUIRED for that type of response.
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The encoding and transport document [RFC2565] defines special rules
for the encoding of these parameters. All other operation elements
are represented using the more generic encoding rules for attributes
and groups of attributes.
3.1.2 Operation IDs and Request IDs
Each IPP operation request includes an identifying "operation-id"
value. Valid values are defined in the "operations-supported"
Printer attribute section (see section 4.4.13). The client specifies
which operation is being requested by supplying the correct
"operation-id" value.
In addition, every invocation of an operation is identified by a
"request-id" value. For each request, the client chooses the
"request-id" which MUST be an integer (possibly unique depending on
client requirements) in the range from 1 to 2**31 - 1 (inclusive).
This "request-id" allows clients to manage multiple outstanding
requests. The receiving IPP object copies all 32-bits of the client-
supplied "request-id" attribute into the response so that the client
can match the response with the correct outstanding request, even if
the "request-id" is out of range. If the request is terminated
before the complete "request-id" is received, the IPP object rejects
the request and returns a response with a "request-id" of 0.
Note: In some cases, the transport protocol underneath IPP might be a
connection oriented protocol that would make it impossible for a
client to receive responses in any order other than the order in
which the corresponding requests were sent. In such cases, the
"request-id" attribute would not be essential for correct protocol
operation. However, in other mappings, the operation responses can
come back in any order. In these cases, the "request-id" would be
essential.
3.1.3 Attributes
Operation requests and responses are both composed of groups of
attributes and/or document data. The attributes groups are:
- Operation Attributes: These attributes are passed in the
operation and affect the IPP object's behavior while processing
the operation request and may affect other attributes or groups
of attributes. Some operation attributes describe the document
data associated with the print job and are associated with new
Job objects, however most operation attributes do not persist
beyond the life of the operation. The description of each
operation attribute includes conformance statements indicating
which operation attributes are REQUIRED and which are OPTIONAL
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for an IPP object to support and which attributes a client MUST
supply in a request and an IPP object MUST supply in a response.
- Job Template Attributes: These attributes affect the processing
of a job. A client OPTIONALLY supplies Job Template Attributes
in a create request, and the receiving object MUST be prepared to
receive all supported attributes. The Job object can later be
queried to find out what Job Template attributes were originally
requested in the create request, and such attributes are returned
in the response as Job Object Attributes. The Printer object can
be queried about its Job Template attributes to find out what
type of job processing capabilities are supported and/or what the
default job processing behaviors are, though such attributes are
returned in the response as Printer Object Attributes. The
"ipp-attribute-fidelity" operation attribute affects processing
of all client-supplied Job Template attributes (see section 15
for a full description of "ipp-attribute-fidelity" and its
relationship to other attributes).
- Job Object Attributes: These attributes are returned in response
to a query operation directed at a Job object.
- Printer Object Attributes: These attributes are returned in
response to a query operation directed at a Printer object.
- Unsupported Attributes: In a create request, the client supplies
a set of Operation and Job Template attributes. If any of these
attributes or their values is unsupported by the Printer object,
the Printer object returns the set of unsupported attributes in
the response. Section 15 gives a full description of how Job
Template attributes supplied by the client in a create request
are processed by the Printer object and how unsupported
attributes are returned to the client. Because of extensibility,
any IPP object might receive a request that contains new or
unknown attributes or values for which it has no support. In such
cases, the IPP object processes what it can and returns the
unsupported attributes in the response.
Later in this section, each operation is formally defined by
identifying the allowed and expected groups of attributes for each
request and response. The model identifies a specific order for each
group in each request or response, but the attributes within each
group may be in any order, unless specified otherwise.
Each attribute specification includes the attribute's name followed
by the name of its attribute syntax(es) in parenthesizes. In
addition, each 'integer' attribute is followed by the allowed range
in parentheses, (m:n), for values of that attribute. Each 'text' or
'name' attribute is followed by the maximum size in octets in
parentheses, (size), for values of that attribute. For more details
on attribute syntax notation, see the descriptions of these
attributes syntaxes in section 4.1.
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Note: Document data included in the operation is not strictly an
attribute, but it is treated as a special attribute group for
ordering purposes. The only operations that support supplying the
document data within an operation request are Print-Job and Send-
Document. There are no operation responses that include document
data.
Note: Some operations are REQUIRED for IPP objects to support; the
others are OPTIONAL (see section 5.2.2). Therefore, before using an
OPTIONAL operation, a client SHOULD first use the REQUIRED Get-
Printer-Attributes operation to query the Printer's "operations-
supported" attribute in order to determine which OPTIONAL Printer and
Job operations are actually supported. The client SHOULD NOT use an
OPTIONAL operation that is not supported. When an IPP object
receives a request to perform an operation it does not support, it
returns the 'server-error-operation-not-supported' status code (see
section 13.1.5.2). An IPP object is non-conformant if it does not
support a REQUIRED operation.
3.1.4 Character Set and Natural Language Operation Attributes
Some Job and Printer attributes have values that are text strings and
names intended for human understanding rather than machine
understanding (see the 'text' and 'name' attribute syntax
descriptions in section 4.1). The following sections describe two
special Operation Attributes called "attributes-charset" and
"attributes-natural-language". These attributes are always part of
the Operation Attributes group. For most attribute groups, the order
of the attributes within the group is not important. However, for
these two attributes within the Operation Attributes group, the order
is critical. The "attributes-charset" attribute MUST be the first
attribute in the group and the "attributes-natural-language"
attribute MUST be the second attribute in the group. In other words,
these attributes MUST be supplied in every IPP request and response,
they MUST come first in the group, and MUST come in the specified
order. For job creation operations, the IPP Printer implementation
saves these two attributes with the new Job object as Job Description
attributes. For the sake of brevity in this document, these
operation attribute descriptions are not repeated with every
operation request and response, but have a reference back to this
section instead.
3.1.4.1 Request Operation Attributes
The client MUST supply and the Printer object MUST support the
following REQUIRED operation attributes in every IPP/1.0 operation
request:
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"attributes-charset" (charset):
This operation attribute identifies the charset (coded character
set and encoding method) used by any 'text' and 'name'
attributes that the client is supplying in this request. It
also identifies the charset that the Printer object MUST use (if
supported) for all 'text' and 'name' attributes and status
messages that the Printer object returns in the response to this
request. See Sections 4.1.1 and 4.1.2 for the specification of
the 'text' and 'name' attribute syntaxes.
All clients and IPP objects MUST support the 'utf-8' charset
[RFC2279] and MAY support additional charsets provided that they
are registered with IANA [IANA-CS]. If the Printer object does
not support the client supplied charset value, the Printer
object MUST reject the request, set the "attributes-charset" to
'utf-8' in the response, and return the 'client-error-charset-
not-supported' status code and any 'text' or 'name' attributes
using the 'utf-8' charset. The Printer object MUST indicate the
charset(s) supported as the values of the "charset-supported"
Printer attribute (see Section 4.4.15), so that the client can
query to determine which charset(s) are supported.
Note to client implementers: Since IPP objects are only required
to support the 'utf-8' charset, in order to maximize
interoperability with multiple IPP object implementations, a
client may want to supply 'utf-8' in the "attributes-charset"
operation attribute, even though the client is only passing and
able to present a simpler charset, such as US-ASCII or ISO-
8859-1. Then the client will have to filter out (or charset
convert) those characters that are returned in the response that
it cannot present to its user. On the other hand, if both the
client and the IPP objects also support a charset in common
besides utf-8, the client may want to use that charset in order
to avoid charset conversion or data loss.
See the 'charset' attribute syntax description in Section 4.1.7
for the syntax and semantic interpretation of the values of this
attribute and for example values.
"attributes-natural-language" (naturalLanguage):
This operation attribute identifies the natural language used by
any 'text' and 'name' attributes that the client is supplying in
this request. This attribute also identifies the natural
language that the Printer object SHOULD use for all 'text' and '
name' attributes and status messages that the Printer object
returns in the response to this request.
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There are no REQUIRED natural languages required for the Printer
object to support. However, the Printer object's "generated-
natural-language-supported" attribute identifies the natural
languages supported by the Printer object and any contained Job
objects for all text strings generated by the IPP object. A
client MAY query this attribute to determine which natural
language(s) are supported for generated messages.
For any of the attributes for which the Printer object generates
text, i.e., for the "job-state-message", "printer-state-
message", and status messages (see Section 3.1.6), the Printer
object MUST be able to generate these text strings in any of its
supported natural languages. If the client requests a natural
language that is not supported, the Printer object MUST return
these generated messages in the Printer's configured natural
language as specified by the Printer's "natural-language-
configured" attribute" (see Section 4.4.16).
For other 'text' and 'name' attributes supplied by the client,
authentication system, operator, system administrator, or
manufacturer (i.e., for "job-originating-user-name", "printer-
name" (name), "printer-location" (text), "printer-info" (text),
and "printer-make-and-model" (text)), the Printer object is only
required to support the configured natural language of the
Printer identified by the Printer object's "natural-language-
configured" attribute, though support of additional natural
languages for these attributes is permitted.
For any 'text' or 'name' attribute in the request that is in a
different natural language than the value supplied in the
"attributes-natural-language" operation attribute, the client
MUST use the Natural Language Override mechanism (see sections
4.1.1.2 and 4.1.2.2) for each such attribute value supplied.
The client MAY use the Natural Language Override mechanism
redundantly, i.e., use it even when the value is in the same
natural language as the value supplied in the "attributes-
natural-language" operation attribute of the request.
The IPP object MUST accept any natural language and any Natural
Language Override, whether the IPP object supports that natural
language or not (and independent of the value of the "ipp-
attribute-fidelity" Operation attribute). That is the IPP
object accepts all client supplied values no matter what the
values are in the Printer object's "generated-natural-language-
supported" attribute. That attribute, "generated-natural-
language-supported", only applies to generated messages,
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not client supplied messages. The IPP object MUST remember that
natural language for all client-supplied attributes, and when
returning those attributes in response to a query, the IPP
object MUST indicate that natural language.
Each value whose attribute syntax type is 'text' or 'name' (see
sections 4.1.1 and 4.1.2) has an Associated Natural-Language.
This document does not specify how this association is stored in
a Printer or Job object. When such a value is encoded in a
request or response, the natural language is either implicit or
explicit:
- In the implicit case, the value contains only the
text/name value, and the language is specified by the
"attributes-natural-language" operation attribute in the
request or response (see sections 4.1.1.1
textWithoutLanguage and 4.1.2.1 nameWithoutLanguage).
- In the explicit case (also known as the Natural-Language
Override case), the value contains both the language and
the text/name value (see sections 4.1.1.2
textWithLanguage and 4.1.2.2 nameWithLanguage).
For example, the "job-name" attribute MAY be supplied by the
client in a create request. The text value for this attribute
will be in the natural language identified by the "attribute-
natural-language" attribute, or if different, as identified by
the Natural Language Override mechanism. If supplied, the IPP
object will use the value of the "job-name" attribute to
populate the Job object's "job-name" attribute. Whenever any
client queries the Job object's "job-name" attribute, the IPP
object returns the attribute as stored and uses the Natural
Language Override mechanism to specify the natural language, if
it is different from that reported in the "attributes-natural-
language" operation attribute of the response. The IPP object
MAY use the Natural Language Override mechanism redundantly,
i.e., use it even when the value is in the same natural language
as the value supplied in the "attributes-natural-language"
operation attribute of the response.
An IPP object MUST NOT reject a request based on a supplied
natural language in an "attributes-natural-language" Operation
attribute or in any attribute that uses the Natural Language
Override.
See the 'naturalLanguage' attribute syntax description in
section 4.1.8 for the syntax and semantic interpretation of the
values of this attribute and for example values.
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Clients SHOULD NOT supply 'text' or 'name' attributes that use an
illegal combination of natural language and charset. For example,
suppose a Printer object supports charsets 'utf-8', 'iso-8859-1', and
'iso-8859-7'. Suppose also, that it supports natural languages 'en'
(English), 'fr' (French), and 'el' (Greek). Although the Printer
object supports the charset 'iso-8859-1' and natural language 'el',
it probably does not support the combination of Greek text strings
using the 'iso-8859-1' charset. The Printer object handles this
apparent incompatibility differently depending on the context in
which it occurs:
- In a create request: If the client supplies a text or name
attribute (for example, the "job-name" operation attribute) that
uses an apparently incompatible combination, it is a client
choice that does not affect the Printer object or its correct
operation. Therefore, the Printer object simply accepts the
client supplied value, stores it with the Job object, and
responds back with the same combination whenever the client (or
any client) queries for that attribute.
- In a query-type operation, like Get-Printer-Attributes: If the
client requests an apparently incompatible combination, the
Printer object responds (as described in section 3.1.4.2) using
the Printer's configured natural language rather than the natural
language requested by the client.
In either case, the Printer object does not reject the request
because of the apparent incompatibility. The potential incompatible
combination of charset and natural language can occur either at the
global operation level or at the Natural Language Override
attribute-by-attribute level. In addition, since the response always
includes explicit charset and natural language information, there is
never any question or ambiguity in how the client interprets the
response.
3.1.4.2 Response Operation Attributes
The Printer object MUST supply and the client MUST support the
following REQUIRED operation attributes in every IPP/1.0 operation
response:
"attributes-charset" (charset):
This operation attribute identifies the charset used by any '
text' and 'name' attributes that the Printer object is returning
in this response. The value in this response MUST be the same
value as the "attributes-charset" operation attribute supplied
by the client in the request. If this is not possible
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(i.e., the charset requested is not supported), the request
would have been rejected. See "attributes-charset" described in
Section 3.1.4.1 above.
If the Printer object supports more than just the 'utf-8'
charset, the Printer object MUST be able to code convert between
each of the charsets supported on a highest fidelity possible
basis in order to return the 'text' and 'name' attributes in the
charset requested by the client. However, some information loss
MAY occur during the charset conversion depending on the
charsets involved. For example, the Printer object may convert
from a UTF-8 'a' to a US-ASCII 'a' (with no loss of
information), from an ISO Latin 1 CAPITAL LETTER A WITH ACUTE
ACCENT to US-ASCII 'A' (losing the accent), or from a UTF-8
Japanese Kanji character to some ISO Latin 1 error character
indication such as '?', decimal code equivalent, or to the
absence of a character, depending on implementation.
Note: Whether an implementation that supports more than one
charset stores the data in the charset supplied by the client or
code converts to one of the other supported charsets, depends on
implementation. The strategy should try to minimize loss of
information during code conversion. On each response, such an
implementation converts from its internal charset to that
requested.
"attributes-natural-language" (naturalLanguage):
This operation attribute identifies the natural language used by
any 'text' and 'name' attributes that the IPP object is
returning in this response. Unlike the "attributes-charset"
operation attribute, the IPP object NEED NOT return the same
value as that supplied by the client in the request. The IPP
object MAY return the natural language of the Job object or the
Printer's configured natural language as identified by the
Printer object's "natural-language-configured" attribute, rather
than the natural language supplied by the client. For any '
text' or 'name' attribute or status message in the response that
is in a different natural language than the value returned in
the "attributes-natural-language" operation attribute, the IPP
object MUST use the Natural Language Override mechanism (see
sections 4.1.1.2 and 4.1.2.2) on each attribute value returned.
The IPP object MAY use the Natural Language Override mechanism
redundantly, i.e., use it even when the value is in the same
natural language as the value supplied in the "attributes-
natural-language" operation attribute of the response.
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3.1.5 Operation Targets
All IPP operations are directed at IPP objects. For Printer
operations, the operation is always directed at a Printer object
using one of its URIs (i.e., one of the values in the Printer
object's "printer-uri-supported" attribute). Even if the Printer
object supports more than one URI, the client supplies only one URI
as the target of the operation. The client identifies the target
object by supplying the correct URI in the "printer-uri (uri)"
operation attribute.
For Job operations, the operation is directed at either:
- The Job object itself using the Job object's URI. In this case,
the client identifies the target object by supplying the correct
URI in the "job-uri (uri)" operation attribute.
- The Printer object that created the Job object using both the
Printer objects URI and the Job object's Job ID. Since the
Printer object that created the Job object generated the Job ID,
it MUST be able to correctly associate the client supplied Job ID
with the correct Job object. The client supplies the Printer
object's URI in the "printer-uri (uri)" operation attribute and
the Job object's Job ID in the "job-id (integer(1:MAX))"
operation attribute.
If the operation is directed at the Job object directly using the Job
object's URI, the client MUST NOT include the redundant "job-id"
operation attribute.
The operation target attributes are REQUIRED operation attributes
that MUST be included in every operation request. Like the charset
and natural language attributes (see section 3.1.4), the operation
target attributes are specially ordered operation attributes. In all
cases, the operation target attributes immediately follow the
"attributes-charset" and "attributes-natural-language" attributes
within the operation attribute group, however the specific ordering
rules are:
- In the case where there is only one operation target attribute
(i.e., either only the "printer-uri" attribute or only the "job-
uri" attribute), that attribute MUST be the third attribute in
the operation attributes group.
- In the case where Job operations use two operation target
attributes (i.e., the "printer-uri" and "job-id" attributes), the
"printer-uri" attribute MUST be the third attribute and the
"job-id" attribute MUST be the fourth attribute.
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In all cases, the target URIs contained within the body of IPP
operation requests and responses must be in absolute format rather
than relative format (a relative URL identifies a resource with the
scope of the HTTP server, but does not include scheme, host or port).
The following rules apply to the use of port numbers in URIs that
identify IPP objects:
1. If the URI scheme allows the port number to be explicitly
included in the URI string, and a port number is specified
within the URI, then that port number MUST be used by the client
to contact the IPP object.
2. If the URI scheme allows the port number to be explicitly
included in the URI string, and a port number is not specified
within the URI, then default port number implied by that URI
scheme MUST be used by the client to contact the IPP object.
3. If the URI scheme does not allow an explicit port number to be
specified within the URI, then the default port number implied
by that URI MUST be used by the client to contact the IPP
object.
Note: The IPP encoding and transport document [RFC2565] shows a
mapping of IPP onto HTTP/1.1 and defines a new default port number
for using IPP over HTTP/1.1.
3.1.6 Operation Status Codes and Messages
Every operation response includes a REQUIRED "status-code" parameter
and an OPTIONAL "status-message" operation attribute. The "status-
code" provides information on the processing of a request. A
"status-message" attribute provides a short textual description of
the status of the operation. The status code is intended for use by
automata, and the status message is intended for the human end user.
If a response does include a "status-message" attribute, an IPP
client NEED NOT examine or display the message, however it SHOULD do
so in some implementation specific manner.
The "status-code" value is a numeric value that has semantic meaning.
The "status-code" syntax is similar to a "type2 enum" (see section
4.1 on "Attribute Syntaxes") except that values can range only from
0x0000 to 0x7FFF. Section 13 describes the status codes, assigns the
numeric values, and suggests a corresponding status message for each
status code. The "status-message" attribute's syntax is "text(255)".
A client implementation of IPP SHOULD convert status code values into
any localized message that has semantic meaning to the end user.
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If the Printer object supports the "status-message" operation
attribute, the Printer object MUST be able to generate this message
in any of the natural languages identified by the Printer object's
"generated-natural-language-supported" attribute (see the
"attributes-natural-language" operation attribute specified in
section 3.1.4.1). As described in section 3.1.4.1 for any returned '
text' attribute, if there is a choice for generating this message,
the Printer object uses the natural language indicated by the value
of the "attributes-natural-language" in the client request if
supported, otherwise the Printer object uses the value in the Printer
object's own "natural-language-configured" attribute. If the Printer
object supports the "status-message" operation attribute, it SHOULD
use the REQUIRED 'utf-8' charset to return a status message for the
following error status codes (see section 13): 'client-error-bad-
request', 'client-error-charset-not-supported', 'server-error-
internal-error', 'server-error-operation-not-supported', and '
server-error-version-not-supported'. In this case, it MUST set the
value of the "attributes-charset" operation attribute to 'utf-8' in
the error response.
3.1.7 Versions
Each operation request and response carries with it a "version-
number" parameter. Each value of the "version-number" is in the form
"X.Y" where X is the major version number and Y is the minor version
number. By including a version number in the client request, it
allows the client to identify which version of IPP it is interested
in using. If the IPP object does not support that version, the
object responds with a status code of 'server-error-version-not-
supported' along with the closest version number that is supported
(see section 13.1.5.4).
There is no version negotiation per se. However, if after receiving
a 'server-error-version-not-supported' status code from an IPP
object, there is nothing that prevents a client from trying again
with a different version number. In order to conform to IPP/1.0, an
implementation MUST support at least version '1.0'.
There is only one notion of "version number" that covers both IPP
Model and IPP Protocol changes. Thus the version number MUST change
when introducing a new version of the Model and Semantics document
[RFC2566] or a new version of the Encoding and Transport document
[RFC2565].
Changes to the major version number indicate structural or syntactic
changes that make it impossible for older version of IPP clients and
Printer objects to correctly parse and process the new or changed
attributes, operations and responses. If the major version number
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changes, the minor version numbers is set to zero. As an example,
adding the "ipp-attribute-fidelity" attribute (if it had not been
part of version '1.0'), would have required a change to the major
version number. Items that might affect the changing of the major
version number include any changes to the Model and Semantics
document [RFC2566] or the Encoding and Transport [RFC2565] itself,
such as:
- reordering of ordered attributes or attribute sets
- changes to the syntax of existing attributes
- changing Operation or Job Template attributes from OPTIONAL to
REQUIRED and vice versa
- adding REQUIRED (for an IPP object to support) operation
attributes
- adding REQUIRED (for an IPP object to support) operation
attribute groups
- adding values to existing operation attributes
- adding REQUIRED operations
Changes to the minor version number indicate the addition of new
features, attributes and attribute values that may not be understood
by all IPP objects, but which can be ignored if not understood.
Items that might affect the changing of the minor version number
include any changes to the model objects and attributes but not the
encoding and transport rules [RFC2565] (except adding attribute
syntaxes). Examples of such changes are:
- grouping all extensions not included in a previous version into
a new version
- adding new attribute values
- adding new object attributes
- adding OPTIONAL (for an IPP object to support) operation
attributes (i.e., those attributes that an IPP object can ignore
without confusing clients)
- adding OPTIONAL (for an IPP object to support) operation
attribute groups (i.e., those attributes that an IPP object can
ignore without confusing clients)
- adding new attribute syntaxes
- adding OPTIONAL operations
- changing Job Description attributes or Printer Description
attributes from OPTIONAL to REQUIRED or vice versa.
The encoding of the "operation-id", the "version-number", the
"status-code", and the "request-id" MUST NOT change over any version
number (either major or minor). This rule guarantees that all future
versions will be backwards compatible with all previous versions (at
least for checking the "operation-id", the "version-number", and the
"request-id"). In addition, any protocol elements (attributes, error
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codes, tags, etc.) that are not carried forward from one version to
the next are deprecated so that they can never be reused with new
semantics.
Implementations that support a certain major version NEED NOT support
ALL previous versions. As each new major version is defined (through
the release of a new specification), that major version will specify
which previous major versions MUST be supported in compliant
implementations.
3.1.8 Job Creation Operations
In order to "submit a print job" and create a new Job object, a
client issues a create request. A create request is any one of
following three operation requests:
- The Print-Job Request: A client that wants to submit a print job
with only a single document uses the Print-Job operation. The
operation allows for the client to "push" the document data to
the Printer object by including the document data in the request
itself.
- The Print-URI Request: A client that wants to submit a print job
with only a single document (where the Printer object "pulls" the
document data instead of the client "pushing" the data to the
Printer object) uses the Print-URI operation. In this case, the
client includes in the request only a URI reference to the
document data (not the document data itself).
- The Create-Job Request: A client that wants to submit a print job
with multiple documents uses the Create-Job operation. This
operation is followed by an arbitrary number of Send-Document
and/or Send-URI operations (each creating another document for
the newly create Job object). The Send-Document operation
includes the document data in the request (the client "pushes"
the document data to the printer), and the Send-URI operation
includes only a URI reference to the document data in the request
(the Printer "pulls" the document data from the referenced
location). The last Send-Document or Send-URI request for a
given Job object includes a "last-document" operation attribute
set to 'true' indicating that this is the last request.
Throughout this model specification, the term "create request" is
used to refer to any of these three operation requests.
A Create-Job operation followed by only one Send-Document operation
is semantically equivalent to a Print-Job operation, however, for
performance reasons, the client SHOULD use the Print-Job operation
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for all single document jobs. Also, Print-Job is a REQUIRED
operation (all implementations MUST support it) whereas Create-Job is
an OPTIONAL operation, hence some implementations might not support
it.
Job submission time is the point in time when a client issues a
create request. The initial state of every Job object is the '
pending' or 'pending-held' state. Later, the Printer object begins
processing the print job. At this point in time, the Job object's
state moves to 'processing'. This is known as job processing time.
There are validation checks that must be done at job submission time
and others that must be performed at job processing time.
At job submission time and at the time a Validate-Job operation is
received, the Printer MUST do the following:
1. Process the client supplied attributes and either accept or
reject the request
2. Validate the syntax of and support for the scheme of any client
supplied URI
At job submission time the Printer object MUST validate whether or
not the supplied attributes, attribute syntaxes, and values are
supported by matching them with the Printer object's corresponding
"xxx-supported" attributes. See section 3.2.1.2 for details. [ipp-
iig] presents suggested steps for an IPP object to either accept or
reject any request and additional steps for processing create
requests.
At job submission time the Printer object NEED NOT perform the
validation checks reserved for job processing time such as:
1. Validating the document data
2. Validating the actual contents of any client supplied URI
(resolve the reference and follow the link to the document data)
At job submission time, these additional job processing time
validation checks are essentially useless, since they require
actually parsing and interpreting the document data, are not
guaranteed to be 100% accurate, and MUST be done, yet again, at job
processing time. Also, in the case of a URI, checking for
availability at job submission time does not guarantee availability
at job processing time. In addition, at job processing time, the
Printer object might discover any of the following conditions that
were not detectable at job submission time:
- runtime errors in the document data,
- nested document data that is in an unsupported format,
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- the URI reference is no longer valid (i.e., the server hosting
the document might be down), or
- any other job processing error
At job processing time, since the Printer object has already
responded with a successful status code in the response to the create
request, if the Printer object detects an error, the Printer object
is unable to inform the end user of the error with an operation
status code. In this case, the Printer, depending on the error, can
set the "job-state", "job-state-reasons", or "job-state-message"
attributes to the appropriate value(s) so that later queries can
report the correct job status.
Note: Asynchronous notification of events is outside the scope of
IPP/1.0.
3.2 Printer Operations
All Printer operations are directed at Printer objects. A client
MUST always supply the "printer-uri" operation attribute in order to
identify the correct target of the operation.
3.2.1 Print-Job Operation
This REQUIRED operation allows a client to submit a print job with
only one document and supply the document data (rather than just a
reference to the data). See Section 15 for the suggested steps for
processing create operations and their Operation and Job Template
attributes.
3.2.1.1 Print-Job Request
The following groups of attributes are supplied as part of the
Print-Job Request:
Group 1: Operation Attributes
Natural Language and Character Set:
The "attributes-charset" and "attributes-natural-language"
attributes as described in section 3.1.4.1. The Printer object
MUST copy these values to the corresponding Job Description
attributes described in sections 4.3.23 and 4.3.24.
Target:
The "printer-uri" (uri) operation attribute which is the target
for this operation as described in section 3.1.5.
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Requesting User Name:
The "requesting-user-name" (name(MAX)) attribute SHOULD be
supplied by the client as described in section 8.3.
"job-name" (name(MAX)):
The client OPTIONALLY supplies this attribute. The Printer
object MUST support this attribute. It contains the client
supplied Job name. If this attribute is supplied by the client,
its value is used for the "job-name" attribute of the newly
created Job object. The client MAY automatically include any
information that will help the end-user distinguish amongst
his/her jobs, such as the name of the application program along
with information from the document, such as the document name,
document subject, or source file name. If this attribute is not
supplied by the client, the Printer generates a name to use in
the "job-name" attribute of the newly created Job object (see
Section 4.3.5).
"ipp-attribute-fidelity" (boolean):
The client OPTIONALLY supplies this attribute. The Printer
object MUST support this attribute. The value 'true' indicates
that total fidelity to client supplied Job Template attributes
and values is required, else the Printer object MUST reject the
Print-Job request. The value 'false' indicates that a
reasonable attempt to print the Job object is acceptable and the
Printer object MUST accept the Print-job request. If not
supplied, the Printer object assumes the value is 'false'. All
Printer objects MUST support both types of job processing. See
section 15 for a full description of "ipp-attribute-fidelity"
and its relationship to other attributes, especially the Printer
object's "pdl-override-supported" attribute.
"document-name" (name(MAX)):
The client OPTIONALLY supplies this attribute. The Printer
object MUST support this attribute. It contains the client
supplied document name. The document name MAY be different than
the Job name. Typically, the client software automatically
supplies the document name on behalf of the end user by using a
file name or an application generated name. If this attribute
is supplied, its value can be used in a manner defined by each
implementation. Examples include: printed along with the Job
(job start sheet, page adornments, etc.), used by accounting or
resource tracking management tools, or even stored along with
the document as a document level attribute. IPP/1.0 does not
support the concept of document level attributes.
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"document-format" (mimeMediaType) :
The client OPTIONALLY supplies this attribute. The Printer
object MUST support this attribute. The value of this attribute
identifies the format of the supplied document data. If the
client does not supply this attribute, the Printer object
assumes that the document data is in the format defined by the
Printer object's "document-format-default" attribute. If the
client supplies this attribute, but the value is not supported
by the Printer object, i.e., the value is not one of the values
of the Printer object's "document-format-supported" attribute,
the Printer object MUST reject the request and return the '
client-error-document-format-not-supported' status code.
"document-natural-language" (naturalLanguage):
The client OPTIONALLY supplies this attribute. The Printer
object OPTIONALLY supports this attribute. This attribute
specifies the natural language of the document for those
document-formats that require a specification of the natural
language in order to image the document unambiguously. There are
no particular values required for the Printer object to support.
"compression" (type3 keyword)
The client OPTIONALLY supplies this attribute. The Printer
object OPTIONALLY supports this attribute and the "compression-
supported" attribute (see section 4.4.29). The client supplied
"compression" operation attribute identifies the compression
algorithm used on the document data. If the client omits this
attribute, the Printer object MUST assume that the data is not
compressed. If the client supplies the attribute and the
Printer object supports the attribute, the Printer object uses
the corresponding decompression algorithm on the document data.
If the client supplies this attribute, but the value is not
supported by the Printer object, i.e., the value is not one of
the values of the Printer object's "compression-supported"
attribute, the Printer object MUST copy the attribute and its
value to the Unsupported Attributes response group, reject the
request, and return the 'client-error-attributes-or-values-not-
supported' status code.
"job-k-octets" (integer(0:MAX))
The client OPTIONALLY supplies this attribute. The Printer
object OPTIONALLY supports this attribute and the "job-k-
octets-supported" attribute (see section 4.4.30). The client
supplied "job-k-octets" operation attribute identifies the total
size of the document(s) in K octets being submitted (see section
4.3.17 for the complete semantics). If the client supplies the
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attribute and the Printer object supports the attribute, the
value of the attribute is used to populate the Job object's
"job-k-octets" Job Description attribute.
Note: For this attribute and the following two attributes
("job-impressions", and "job-media-sheets"), if the client
supplies the attribute, but the Printer object does not support
the attribute, the Printer object ignores the client-supplied
value. If the client supplies the attribute and the Printer
supports the attribute, and the value is within the range of the
corresponding Printer object's "xxx-supported" attribute, the
Printer object MUST use the value to populate the Job object's
"xxx" attribute. If the client supplies the attribute and the
Printer supports the attribute, but the value is outside the
range of the corresponding Printer object's "xxx-supported"
attribute, the Printer object MUST copy the attribute and its
value to the Unsupported Attributes response group, reject the
request, and return the 'client-error-attributes-or-values-not-
supported' status code. If the client does not supply the
attribute, the Printer object MAY choose to populate the
corresponding Job object attribute depending on whether the
Printer object supports the attribute and is able to calculate
or discern the correct value.
"job-impressions" (integer(0:MAX))
The client OPTIONALLY supplies this attribute. The Printer
object OPTIONALLY supports this attribute and the "job-
impressions-supported" attribute (see section 4.4.31). The
client supplied "job-impressions" operation attribute identifies
the total size in number of impressions of the document(s) being
submitted (see section 4.3.18 for the complete semantics).
See note under "job-k-octets".
"job-media-sheets" (integer(0:MAX))
The client OPTIONALLY supplies this attribute. The Printer
object OPTIONALLY supports this attribute and the "job-media-
sheets-supported" attribute (see section 4.4.32). The client
supplied "job-media-sheets" operation attribute identifies the
total number of media sheets to be produced for this job (see
section 4.3.19 for the complete semantics).
See note under "job-k-octets".
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Group 2: Job Template Attributes
The client OPTIONALLY supplies a set of Job Template attributes
as defined in section 4.2. If the client is not supplying any
Job Template attributes in the request, the client SHOULD omit
Group 2 rather than sending an empty group. However, a Printer
object MUST be able to accept an empty group.
Group 3: Document Content
The client MUST supply the document data to be processed.
Note: In addition to the MANDATORY parameters required for every
operation request, the simplest Print-Job Request consists of just
the "attributes-charset" and "attributes-natural-language" operation
attributes; the "printer-uri" target operation attribute; the
Document Content and nothing else. In this simple case, the Printer
object:
- creates a new Job object (the Job object contains a single
document),
- stores a generated Job name in the "job-name" attribute in the
natural language and charset requested (see Section 3.1.4.1) (if
those are supported, otherwise using the Printer object's default
natural language and charset), and
- at job processing time, uses its corresponding default value
attributes for the supported Job Template attributes that were
not supplied by the client as IPP attribute or embedded
instructions in the document data.
3.2.1.2 Print-Job Response
The Printer object MUST return to the client the following sets
of attributes as part of the Print-Job Response:
Group 1: Operation Attributes
Status Message:
In addition to the REQUIRED status code returned in every
response, the response OPTIONALLY includes a "status-message"
(text) operation attribute as described in sections 14 and
3.1.6. If the client supplies unsupported or conflicting Job
Template attributes or values, the Printer object MUST reject or
accept the Print-Job request depending on the whether the client
supplied a 'true' or 'false' value for the "ipp-attribute-
fidelity" operation attribute. See the Implementer's Guide
[ipp-iig] for a complete description of the suggested steps for
processing a create request.
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Natural Language and Character Set:
The "attributes-charset" and "attributes-natural-language"
attributes as described in section 3.1.4.2.
Group 2: Unsupported Attributes
This is a set of Operation and Job Template attributes supplied
by the client (in the request) that are not supported by the
Printer object or that conflict with one another (see the
Implementer's Guide [ipp-iig]). If the Printer object is not
returning any Unsupported Attributes in the response, the
Printer object SHOULD omit Group 2 rather than sending an empty
group. However, a client MUST be able to accept an empty group.
Unsupported attributes fall into three categories:
1. The Printer object does not support the supplied attribute
(no matter what the attribute syntax or value).
2. The Printer object does support the attribute, but does not
support some or all of the particular attribute syntaxes or
values supplied by the client (i.e., the Printer object does
not have those attribute syntaxes or values in its
corresponding "xxx-supported" attribute).
3. The Printer object does support the attributes and values
supplied, but the particular values are in conflict with one
another, because they violate a constraint, such as not being
able to staple transparencies.
In the case of an unsupported attribute name, the Printer object
returns the client-supplied attribute with a substituted "out-
of-band" value of 'unsupported' indicating no support for the
attribute itself (see the beginning of section 4.1).
In the case of a supported attribute with one or more
unsupported attribute syntaxes or values, the Printer object
simply returns the client-supplied attribute with the
unsupported attribute syntaxes or values as supplied by the
client. This indicates support for the attribute, but no
support for that particular attribute syntax or value. If the
client supplies a multi-valued attribute with more than one
value and the Printer object supports the attribute but only
supports a subset of the client-supplied attribute syntaxes or
values, the Printer object MUST return only those attribute
syntaxes or values that are unsupported.
In the case of two (or more) supported attribute values that are
in conflict with one another (although each is supported
independently, the values conflict when requested together
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within the same job), the Printer object MUST return all the
values that it ignores or substitutes to resolve the conflict,
but not any of the values that it is still using. The choice
for exactly how to resolve the conflict is implementation
dependent. See The Implementer's Guide [ipp-iig] for an
example.
In these three cases, the value of the "ipp-attribute-fidelity"
supplied by the client does not affect what the Printer object
returns. The value of "ipp-attribute-fidelity" only affects
whether the Print-Job operation is accepted or rejected. If the
job is accepted, the client may query the job using the Get-
Job-Attributes operation requesting the unsupported attributes
that were returned in the create response to see which
attributes were ignored (not stored on the Job object) and which
attributes were stored with other (substituted) values.
Group 3: Job Object Attributes
"job-uri" (uri):
The Printer object MUST return the Job object's URI by returning
the contents of the REQUIRED "job-uri" Job object attribute.
The client uses the Job object's URI when directing operations
at the Job object. The Printer object always uses its
configured security policy when creating the new URI. However,
if the Printer object supports more than one URI, the Printer
object also uses information about which URI was used in the
Print-Job Request to generated the new URI so that the new URI
references the correct access channel. In other words, if the
Print-Job Request comes in over a secure channel, the Printer
object MUST generate a Job URI that uses the secure channel as
well.
"job-id" (integer(1:MAX)):
The Printer object MUST return the Job object's Job ID by
returning the REQUIRED "job-id" Job object attribute. The
client uses this "job-id" attribute in conjunction with the
"printer-uri" attribute used in the Print-Job Request when
directing Job operations at the Printer object.
"job-state":
The Printer object MUST return the Job object's REQUIRED "job-
state" attribute. The value of this attribute (along with the
value of the next attribute "job-state-reasons") is taken from a
"snapshot" of the new Job object at some meaningful point in
time (implementation defined) between when the Printer object
receives the Print-Job Request and when the Printer object
returns the response.
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"job-state-reasons":
The Printer object OPTIONALLY returns the Job object's OPTIONAL
"job-state-reasons" attribute. If the Printer object supports
this attribute then it MUST be returned in the response. If
this attribute is not returned in the response, the client can
assume that the "job-state-reasons" attribute is not supported
and will not be returned in a subsequent Job object query.
"job-state-message":
The Printer object OPTIONALLY returns the Job object's OPTIONAL
"job-state-message" attribute. If the Printer object supports
this attribute then it MUST be returned in the response. If
this attribute is not returned in the response, the client can
assume that the "job-state-message" attribute is not supported
and will not be returned in a subsequent Job object query.
"number-of-intervening-jobs":
The Printer object OPTIONALLY returns the Job object's OPTIONAL
"number-of-intervening-jobs" attribute. If the Printer object
supports this attribute then it MUST be returned in the
response. If this attribute is not returned in the response,
the client can assume that the "number-of-intervening-jobs"
attribute is not supported and will not be returned in a
subsequent Job object query.
Note: Since any printer state information which affects a job's
state is reflected in the "job-state" and "job-state-reasons"
attributes, it is sufficient to return only these attributes and
no specific printer status attributes.
Note: In addition to the MANDATORY parameters required for every
operation response, the simplest response consists of the just the
"attributes-charset" and "attributes-natural-language" operation
attributes and the "job-uri", "job-id", and "job-state" Job Object
Attributes. In this simplest case, the status code is "successful-
ok" and there is no "status-message" operation attribute.
3.2.2 Print-URI Operation
This OPTIONAL operation is identical to the Print-Job operation
(section 3.2.1) except that a client supplies a URI reference to the
document data using the "document-uri" (uri) operation attribute (in
Group 1) rather than including the document data itself. Before
returning the response, the Printer MUST validate that the Printer
supports the retrieval method (e.g., http, ftp, etc.) implied by the
URI, and MUST check for valid URI syntax. If the client-supplied URI
scheme is not supported, i.e. the value is not in the Printer
object's "referenced-uri-scheme-supported" attribute, the Printer
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object MUST reject the request and return the 'client-error-uri-
scheme-not-supported' status code. See The Implementer's Guide
[ipp-iig] for suggested additional checks. The Printer NEED NOT
follow the reference and validate the contents of the reference.
If the Printer object supports this operation, it MUST support the
"reference-uri-schemes-supported" Printer attribute (see section
4.4.24).
It is up to the IPP object to interpret the URI and subsequently
"pull" the document from the source referenced by the URI string.
3.2.3 Validate-Job Operation
This REQUIRED operation is similar to the Print-Job operation
(section 3.2.1) except that a client supplies no document data and
the Printer allocates no resources (i.e., it does not create a new
Job object). This operation is used only to verify capabilities of a
printer object against whatever attributes are supplied by the client
in the Validate-Job request. By using the Validate-Job operation a
client can validate that an identical Print-Job operation (with the
document data) would be accepted. The Validate-Job operation also
performs the same security negotiation as the Print-Job operation
(see section 8), so that a client can check that the client and
Printer object security requirements can be met before performing a
Print-Job operation.
Note: The Validate-Job operation does not accept a "document-uri"
attribute in order to allow a client to check that the same Print-URI
operation will be accepted, since the client doesn't send the data
with the Print-URI operation. The client SHOULD just issue the
Print-URI request.
The Printer object returns the same status codes, Operation
Attributes (Group 1) and Unsupported Attributes (Group 2) as the
Print-Job operation. However, no Job Object Attributes (Group 3) are
returned, since no Job object is created.
3.2.4 Create-Job Operation
This OPTIONAL operation is similar to the Print-Job operation
(section 3.2.1) except that in the Create-Job request, a client does
not supply document data or any reference to document data. Also,
the client does not supply any of the "document-name", "document-
format", "compression", or "document-natural-language" operation
attributes. This operation is followed by one or more Send-Document
or Send-URI operations. In each of those operation requests, the
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client OPTIONALLY supplies the "document-name", "document-format",
and "document-natural-language" attributes for each document in the
multi-document Job object.
If a Printer object supports the Create-Job operation, it MUST also
support the Send-Document operation and also MAY support the Send-URI
operation.
If the Printer object supports this operation, it MUST support the
"multiple-operation-time-out" Printer attribute (see section 4.4.28).
3.2.5 Get-Printer-Attributes Operation
This REQUIRED operation allows a client to request the values of the
attributes of a Printer object. In the request, the client supplies
the set of Printer attribute names and/or attribute group names in
which the requester is interested. In the response, the Printer
object returns a corresponding attribute set with the appropriate
attribute values filled in.
For Printer objects, the possible names of attribute groups are:
- 'job-template': all of the Job Template attributes that apply to
a Printer object (the last two columns of the table in Section
4.2).
- 'printer-description': the attributes specified in Section 4.4.
- 'all': the special group 'all' that includes all supported
attributes.
Since a client MAY request specific attributes or named groups, there
is a potential that there is some overlap. For example, if a client
requests, 'printer-name' and 'all', the client is actually requesting
the "printer-name" attribute twice: once by naming it explicitly, and
once by inclusion in the 'all' group. In such cases, the Printer
object NEED NOT return each attribute only once in the response even
if it is requested multiple times. The client SHOULD NOT request the
same attribute in multiple ways.
It is NOT REQUIRED that a Printer object support all attributes
belonging to a group (since some attributes are OPTIONAL). However,
it is REQUIRED that each Printer object support all group names.
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3.2.5.1 Get-Printer-Attributes Request
The following sets of attributes are part of the Get-Printer-
Attributes Request:
Group 1: Operation Attributes
Natural Language and Character Set:
attributes-charset" and "attributes-natural-language" butes as
described in section 3.1.4.1.
Target:
The "printer-uri" (uri) operation attribute which is the target
for this operation as described in section 3.1.5.
Requesting User Name:
The "requesting-user-name" (name(MAX)) attribute SHOULD be
supplied by the client as described in section 8.3.
"requested-attributes" (1setOf keyword) :
The client OPTIONALLY supplies a set of attribute names and/or
attribute group names in whose values the requester is
interested. The Printer object MUST support this attribute. If
the client omits this attribute, the Printer MUST respond as if
this attribute had been supplied with a value of 'all'.
"document-format" (mimeMediaType) :
The client OPTIONALLY supplies this attribute. The Printer
object MUST support this attribute. This attribute is useful
for a Printer object to determine the set of supported attribute
values that relate to the requested document format. The
Printer object MUST return the attributes and values that it
uses to validate a job on a create or Validate-Job operation in
which this document format is supplied. The Printer object
SHOULD return only (1) those attributes that are supported for
the specified format and (2) the attribute values that are
supported for the specified document format. By specifying the
document format, the client can get the Printer object to
eliminate the attributes and values that are not supported for a
specific document format. For example, a Printer object might
have multiple interpreters to support both '
application/postscript' (for PostScript) and 'text/plain' (for
text) documents. However, for only one of those interpreters
might the Printer object be able to support "number-up" with
values of '1', '2', and '4'. For the other interpreter it might
be able to only support "number-up" with a value of '1'. Thus a
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client can use the Get-Printer-Attributes operation to obtain
the attributes and values that will be used to accept/reject a
create job operation.
If the Printer object does not distinguish between different
sets of supported values for each different document format when
validating jobs in the create and Validate-Job operations, it
MUST NOT distinguish between different document formats in the
Get-Printer-Attributes operation. If the Printer object does
distinguish between different sets of supported values for each
different document format specified by the client, this
specialization applies only to the following Printer object
attributes:
- Printer attributes that are Job Template attributes ("xxx-
default" "xxx-supported", and "xxx-ready" in the Table in
Section 4.2),
- "pdl-override-supported",
- "compression-supported",
- "job-k-octets-supported",
- "job-impressions-supported,
- "job-media-sheets-supported"
- "printer-driver-installer",
- "color-supported", and
- "reference-uri-schemes-supported"
The values of all other Printer object attributes (including
"document-format-supported") remain invariant with respect to
the client supplied document format (except for new Printer
description attribute as registered according to section 6.2).
If the client omits this "document-format" operation attribute,
the Printer object MUST respond as if the attribute had been
supplied with the value of the Printer object's "document-
format-default" attribute. It is recommended that the client
always supply a value for "document-format", since the Printer
object's "document-format-default" may be 'application/octet-
stream', in which case the returned attributes and values are
for the union of the document formats that the Printer can
automatically sense. For more details, see the description of
the 'mimeMediaType' attribute syntax in section 4.1.9.
If the client supplies a value for the "document-format"
Operation attribute that is not supported by the Printer, i.e.,
is not among the values of the Printer object's "document-
format-supported" attribute, the Printer object MUST reject the
operation and return the 'client-error-document-format-not-
supported' status code.
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3.2.5.2 Get-Printer-Attributes Response
The Printer object returns the following sets of attributes as part
of the Get-Printer-Attributes Response:
Group 1: Operation Attributes
Status Message:
In addition to the REQUIRED status code returned in every
response, the response OPTIONALLY includes a "status-message"
(text) operation attribute as described in section 3.1.6.
Natural Language and Character Set:
The "attributes-charset" and "attributes-natural-language"
attributes as described in section 3.1.4.2.
Group 2: Unsupported Attributes
This is a set of Operation attributes supplied by the client (in
the request) that are not supported by the Printer object or
that conflict with one another (see sections 3.2.1.2 and 16).
The response NEED NOT contain the "requested-attributes"
operation attribute with any supplied values (attribute
keywords) that were requested by the client but are not
supported by the IPP object. If the Printer object is not
returning any Unsupported Attributes in the response, the
Printer object SHOULD omit Group 2 rather than sending an empty
group. However, a client MUST be able to accept an empty group.
Group 3: Printer Object Attributes
This is the set of requested attributes and their current
values. The Printer object ignores (does not respond with) any
requested attribute which is not supported. The Printer object
MAY respond with a subset of the supported attributes and
values, depending on the security policy in force. However, the
Printer object MUST respond with the 'unknown' value for any
supported attribute (including all REQUIRED attributes) for
which the Printer object does not know the value. Also the
Printer object MUST respond with the 'no-value' for any
supported attribute (including all REQUIRED attributes) for
which the system administrator has not configured a value. See
the description of the "out-of-band" values in the beginning of
Section 4.1.
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3.2.6 Get-Jobs Operation
This REQUIRED operation allows a client to retrieve the list of Job
objects belonging to the target Printer object. The client may also
supply a list of Job attribute names and/or attribute group names. A
group of Job object attributes will be returned for each Job object
that is returned.
This operation is similar to the Get-Job-Attributes operation, except
that this Get-Jobs operation returns attributes from possibly more
than one object (see the description of Job attribute group names in
section 3.3.4).
3.2.6.1 Get-Jobs Request
The client submits the Get-Jobs request to a Printer object.
The following groups of attributes are part of the Get-Jobs Request:
Group 1: Operation Attributes
Natural Language and Character Set:
The "attributes-charset" and "attributes-natural-language"
attributes as described in section 3.1.4.1.
Target:
The "printer-uri" (uri) operation attribute which is the target
for this operation as described in section 3.1.5.
Requesting User Name:
The "requesting-user-name" (name(MAX)) attribute SHOULD be
supplied by the client as described in section 8.3.
"limit" (integer(1:MAX)):
The client OPTIONALLY supplies this attribute. The Printer
object MUST support this attribute. It is an integer value that
indicates a limit to the number of Job objects returned. The
limit is a "stateless limit" in that if the value supplied by
the client is 'N', then only the first 'N' jobs are returned in
the Get-Jobs Response. There is no mechanism to allow for the
next 'M' jobs after the first 'N' jobs. If the client does not
supply this attribute, the Printer object responds with all
applicable jobs.
"requested-attributes" (1setOf keyword):
The client OPTIONALLY supplies this attribute. The Printer
object MUST support this attribute. It is a set of Job
attribute names and/or attribute groups names in whose values
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the requester is interested. This set of attributes is returned
for each Job object that is returned. The allowed attribute
group names are the same as those defined in the Get-Job-
Attributes operation in section 3.3.4. If the client does not
supply this attribute, the Printer MUST respond as if the client
had supplied this attribute with two values: 'job-uri' and '
job-id'.
"which-jobs" (type2 keyword):
The client OPTIONALLY supplies this attribute. The Printer
object MUST support this attribute. It indicates which Job
objects MUST be returned by the Printer object. The values for
this attribute are:
'completed': This includes any Job object whose state is
'completed', 'canceled', or 'aborted'.
'not-completed': This includes any Job object whose state is '
pending', 'processing', 'processing-stopped', or 'pending-
held'.
A Printer object MUST support both values. However, if the
mentation does not keep jobs in the 'completed', 'canceled', '
aborted' states, then it returns no jobs when the 'completed'
value is supplied.
If a client supplies some other value, the Printer object MUST
copy the attribute and the unsupported value to the Unsupported
Attributes response group, reject the request, and return the '
client-error-attributes-or-values-not-supported' status code.
If the client does not supply this attribute, the Printer object
MUST respond as if the client had supplied the attribute with a
value of 'not-completed'.
"my-jobs" (boolean):
The client OPTIONALLY supplies this attribute. The Printer
object MUST support this attribute. It indicates whether all
jobs or just the jobs submitted by the requesting user of this
request MUST be returned by the Printer object. If the client
does not supply this attribute, the Printer object MUST respond
as if the client had supplied the attribute with a value of '
false', i.e., all jobs. The means for authenticating the
requesting user and matching the jobs is described in section 8.
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3.2.6.2 Get-Jobs Response
The Printer object returns all of the Job objects that match the
criteria as defined by the attribute values supplied by the client in
the request. It is possible that no Job objects are returned since
there may literally be no Job objects at the Printer, or there may be
no Job objects that match the criteria supplied by the client. If
the client requests any Job attributes at all, there is a set of Job
Object Attributes returned for each Job object.
Group 1: Operation Attributes
Status Message:
In addition to the REQUIRED status code returned in every
response, the response OPTIONALLY includes a "status-message"
(text) operation attribute as described in sections 14 and
3.1.6.
Natural Language and Character Set:
The "attributes-charset" and "attributes-natural-language"
attributes as described in section 3.1.4.2.
Group 2: Unsupported Attributes
This is a set of Operation attributes supplied by the client (in
the request) that are not supported by the Printer object or
that conflict with one another (see sections 3.2.1.2 and the
Implementer's Guide [ipp-iig]). The response NEED NOT contain
the "requested-attributes" operation attribute with any supplied
values (attribute keywords) that were requested by the client
but are not supported by the IPP object. If the Printer object
is not returning any Unsupported Attributes in the response, the
Printer object SHOULD omit Group 2 rather than sending an empty
group. However, a client MUST be able to accept an empty group.
Groups 3 to N: Job Object Attributes
The Printer object responds with one set of Job Object
Attributes for each returned Job object. The Printer object
ignores (does not respond with) any requested attribute or value
which is not supported or which is restricted by the security
policy in force, including whether the requesting user is the
user that submitted the job (job originating user) or not (see
section 8). However, the Printer object MUST respond with the '
unknown' value for any supported attribute (including all
REQUIRED attributes) for which the Printer object does not know
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the value, unless it would violate the security policy. See the
description of the "out-of-band" values in the beginning of
Section 4.1.
Jobs are returned in the following order:
- If the client requests all 'completed' Jobs (Jobs in the '
completed', 'aborted', or 'canceled' states), then the Jobs
are returned newest to oldest (with respect to actual
completion time)
- If the client requests all 'not-completed' Jobs (Jobs in the
'pending', 'processing', 'pending-held', and 'processing-
stopped' states), then Jobs are returned in relative
chronological order of expected time to complete (based on
whatever scheduling algorithm is configured for the Printer
object).
3.3 Job Operations
All Job operations are directed at Job objects. A client MUST always
supply some means of identifying the Job object in order to identify
the correct target of the operation. That job identification MAY
either be a single Job URI or a combination of a Printer URI with a
Job ID. The IPP object implementation MUST support both forms of
identification for every job.
3.3.1 Send-Document Operation
This OPTIONAL operation allows a client to create a multi-document
Job object that is initially "empty" (contains no documents). In the
Create-Job response, the Printer object returns the Job object's URI
(the "job-uri" attribute) and the Job object's 32-bit identifier (the
"job-id" attribute). For each new document that the client desires
to add, the client uses a Send-Document operation. Each Send-
Document Request contains the entire stream of document data for one
document.
Since the Create-Job and the send operations (Send-Document or Send-
URI operations) that follow could occur over an arbitrarily long
period of time for a particular job, a client MUST send another send
operation within an IPP Printer defined minimum time interval after
the receipt of the previous request for the job. If a Printer object
supports multiple document jobs, the Printer object MUST support the
"multiple-operation-time-out" attribute (see section 4.4.28). This
attribute indicates the minimum number of seconds the Printer object
will wait for the next send operation before taking some recovery
action.
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An IPP object MUST recover from an errant client that does not supply
a send operation, sometime after the minimum time interval specified
by the Printer object's "multiple-operation-time-out" attribute.
Such recovery MAY include any of the following or other recovery
actions:
1. Assume that the Job is an invalid job, start the process of
changing the job state to 'aborted', add the 'aborted-by-system'
value to the job's "job-state-reasons" attribute (see section
4.3.8), if supported, and clean up all resources associated with
the Job. In this case, if another send operation is finally
received, the Printer responds with an "client-error-not-
possible" or "client-error-not-found" depending on whether or
not the Job object is still around when the send operation
finally arrives.
2. Assume that the last send operation received was in fact the
last document (as if the "last-document" flag had been set to '
true'), close the Job object, and proceed to process it (i.e.,
move the Job's state to 'pending').
3. Assume that the last send operation received was in fact the
last document, close the Job, but move it to the 'pending-held'
and add the 'submission-interrupted' value to the job's "job-
state-reasons" attribute (see section 4.3.8), if supported.
This action allows the user or an operator to determine whether
to continue processing the Job by moving it back to the '
pending' state or to cancel the job.
Each implementation is free to decide the "best" action to take
depending on local policy, whether any documents have been added,
whether the implementation spools jobs or not, and/or any other piece
of information available to it. If the choice is to abort the Job
object, it is possible that the Job object may already have been
processed to the point that some media sheet pages have been printed.
3.3.1.1 Send-Document Request
The following attribute sets are part of the Send-Document Request:
Group 1: Operation Attributes
Natural Language and Character Set:
The "attributes-charset" and "attributes-natural-language"
attributes as described in section 3.1.4.1.
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Target:
Either (1) the "printer-uri" (uri) plus "job-id"
(integer(1:MAX))or (2) the "job-uri" (uri) operation
attribute(s) which define the target for this operation as
described in section 3.1.5.
Requesting User Name:
"requesting-user-name" (name(MAX)) attribute SHOULD be supplied
by the client as described in section 8.3.
"document-name" (name(MAX)):
The client OPTIONALLY supplies this attribute. The Printer
object MUST support this attribute. It contains the client
supplied document name. The document name MAY be different than
the Job name. It might be helpful, but NEED NOT be unique
across multiple documents in the same Job. Typically, the
client software automatically supplies the document name on
behalf of the end user by using a file name or an application
generated name. See the description of the "document-name"
operation attribute in the Print-Job Request (section 3.2.1.1)
for more information about this attribute
"document-format" (mimeMediaType):
The client OPTIONALLY supplies this attribute. The Printer
object MUST support this attribute. The value of this attribute
identifies the format of the supplied document data. If the
client does not supply this attribute, the Printer object
assumes that the document data is in the format defined by the
Printer object's "document-format-default" attribute. If the
client supplies this attribute, but the value is not supported
by the Printer object, i.e., the value is not one of the values
of the Printer object's "document-format-supported" attribute,
the Printer object MUST reject the request and return the '
client-error-document-format-not-supported' status code.
"document-natural-language" (naturalLanguage):
The client OPTIONALLY supplies this attribute. The Printer
object OPTIONALLY supports this attribute. This attribute
specifies the natural language of the document for those
document-formats that require a specification of the natural
language in order to image the document unambiguously. There
are no particular values required for the Printer object to
support.
"compression" (type3 keyword)
The client OPTIONALLY supplies this attribute. The Printer
object OPTIONALLY supports this attribute and the "compression-
supported" attribute (see section 4.4.29). The client supplied
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"compression" operation attribute identifies the compression
algorithm used on the document data. If the client omits this
attribute, the Printer object MUST assume that the data is not
compressed. If the client supplies the attribute and the
Printer object supports the attribute, the Printer object MUST
use the corresponding decompression algorithm on the document
data. If the client supplies this attribute, but the value is
not supported by the Printer object, i.e., the value is not one
of the values of the Printer object's "compression-supported"
attribute, the Printer object MUST copy the attribute and its
value to the Unsupported Attributes response group, reject the
request, and return the 'client-error-attributes-or-values-not-
supported' status code.
"last-document" (boolean):
The client MUST supply this attribute. The Printer object MUST
support this attribute. It is a boolean flag that is set to '
true' if this is the last document for the Job, 'false'
otherwise.
Group 2: Document Content
The client MUST supply the document data if the "last-document"
flag is set to 'false'. However, since a client might not know
that the previous document sent with a Send-Document (or Send-
URI) operation was the last document (i.e., the "last-document"
attribute was set to 'false'), it is legal to send a Send-
Document request with no document data where the "last-document"
flag is set to 'true'. Such a request MUST NOT increment the
value of the Job object's "number-of-documents" attribute, since
no real document was added to the job.
3.3.1.2 Send-Document Response
The following sets of attributes are part of the Send-Document
Response:
Group 1: Operation Attributes
Status Message:
In addition to the REQUIRED status code returned in every
response, the response OPTIONALLY includes a "status-message"
(text) operation attribute as described in sections 14 and
3.1.6.
Natural Language and Character Set:
The "attributes-charset" and "attributes-natural-language"
attributes as described in section 3.1.4.2.
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Group 2: Unsupported Attributes
This is a set of Operation attributes supplied by the client (in
the request) that are not supported by the Printer object or
that conflict with one another (see sections 3.2.1.2 and the
Implementer's Guide [ipp-iig]). If the Printer object is not
returning any Unsupported Attributes in the response, the
Printer object SHOULD omit Group 2 rather than sending an empty
group. However, a client MUST be able to accept an empty group.
Group 3: Job Object Attributes
This is the same set of attributes as described in the Print-Job
response (see section 3.2.1.2).
3.3.2 Send-URI Operation
This OPTIONAL operation is identical to the Send-Document operation
(see section 3.3.1) except that a client MUST supply a URI reference
("document-uri" operation attribute) rather than the document data
itself. If a Printer object supports this operation, clients can use
both Send-URI or Send-Document operations to add new documents to an
existing multi-document Job object. However, if a client needs to
indicate that the previous Send-URI or Send-Document was the last
document, the client MUST use the Send-Document operation with no
document data and the "last-document" flag set to 'true' (rather than
using a Send-URI operation with no "document-uri" operation
attribute).
If a Printer object supports this operation, it MUST also support the
Print-URI operation (see section 3.2.2).
The Printer object MUST validate the syntax and URI scheme of the
supplied URI before returning a response, just as in the Print-URI
operation.
3.3.3 Cancel-Job Operation
This REQUIRED operation allows a client to cancel a Print Job from
the time the job is created up to the time it is completed, canceled,
or aborted. Since a Job might already be printing by the time a
Cancel-Job is received, some media sheet pages might be printed
before the job is actually terminated.
3.3.3.1 Cancel-Job Request
The following groups of attributes are part of the Cancel-Job
Request:
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Group 1: Operation Attributes
Natural Language and Character Set:
The "attributes-charset" and "attributes-natural-language"
attributes as described in section 3.1.4.1.
Target:
Either (1) the "printer-uri" (uri) plus "job-id"
(integer(1:MAX))or (2) the "job-uri" (uri) operation
attribute(s) which define the target for this operation as
described in section 3.1.5.
Requesting User Name:
The "requesting-user-name" (name(MAX)) attribute SHOULD be
supplied by the client as described in section 8.3.
"message" (text(127)):
The client OPTIONALLY supplies this attribute. The Printer
object OPTIONALLY supports this attribute. It is a message to
the operator. This "message" attribute is not the same as the
"job-message-from-operator" attribute. That attribute is used
to report a message from the operator to the end user that
queries that attribute. This "message" operation attribute is
used to send a message from the client to the operator along
with the operation request. It is an implementation decision of
how or where to display this message to the operator (if at
all).
3.3.3.2 Cancel-Job Response
The following sets of attributes are part of the Cancel-Job Response:
Group 1: Operation Attributes
Status Message:
In addition to the REQUIRED status code returned in every
response, the response OPTIONALLY includes a "status-message"
(text) operation attribute as described in sections 14 and
3.1.6.
If the job is already in the 'completed', 'aborted', or '
canceled' state, or the 'process-to-stop-point' value is set in
the Job's "job-state-reasons" attribute, the Printer object MUST
reject the request and return the 'client-error-not-possible'
error status code.
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Natural Language and Character Set:
The "attributes-charset" and "attributes-natural-language"
attributes as described in section 3.1.4.2.
Group 2: Unsupported Attributes
This is a set of Operation attributes supplied by the client (in
the request) that are not supported by the Printer object or
that conflict with one another (see section 3.2.1.2 and the
Implementer's Guide [ipp-iig]). If the Printer object is not
returning any Unsupported Attributes in the response, the
Printer object SHOULD omit Group 2 rather than sending an empty
group. However, a client MUST be able to accept an empty group.
Once a successful response has been sent, the implementation
guarantees that the Job will eventually end up in the 'canceled'
state. Between the time of the Cancel-Job operation is accepted and
when the job enters the 'canceled' job-state (see section 4.3.7), the
"job-state-reasons" attribute SHOULD contain the 'processing-to-
stop-point' value which indicates to later queries that although the
Job might still be 'processing', it will eventually end up in the '
canceled' state, not the 'completed' state.
3.3.4 Get-Job-Attributes Operation
This REQUIRED operation allows a client to request the values of
attributes of a Job object and it is almost identical to the Get-
Printer-Attributes operation (see section 3.2.5). The only
differences are that the operation is directed at a Job object rather
than a Printer object, there is no "document-format" operation
attribute used when querying a Job object, and the returned attribute
group is a set of Job object attributes rather than a set of Printer
object attributes.
For Jobs, the possible names of attribute groups are:
- 'job-template': all of the Job Template attributes that apply to a
Job object (the first column of the table in Section 4.2).
- 'job-description': all of the Job Description attributes specified
in Section 4.3.
- 'all': the special group 'all' that includes all supported
attributes.
Since a client MAY request specific attributes or named groups, there
is a potential that there is some overlap. For example, if a client
requests, 'job-name' and 'job-description', the client is actually
requesting the "job-name" attribute once by naming it explicitly, and
once by inclusion in the 'job-description' group. In such cases, the
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Printer object NEED NOT return the attribute only once in the
response even if it is requested multiple times. The client SHOULD
NOT request the same attribute in multiple ways.
It is NOT REQUIRED that a Job object support all attributes belonging
to a group (since some attributes are OPTIONAL). However it is
REQUIRED that each Job object support all group names.
3.3.4.1 Get-Job-Attributes Request
The following groups of attributes are part of the Get-Job-Attributes
Request when the request is directed at a Job object:
Group 1: Operation Attributes
Natural Language and Character Set:
The "attributes-charset" and "attributes-natural-language"
attributes as described in section 3.1.4.1.
Target:
Either (1) the "printer-uri" (uri) plus "job-id"
(integer(1:MAX)) or (2) the "job-uri" (uri) operation
attribute(s) which define the target for this operation as
described in section 3.1.5.
Requesting User Name:
The "requesting-user-name" (name(MAX)) attribute SHOULD be
supplied by the client as described in section 8.3.
"requested-attributes" (1setOf keyword) :
The client OPTIONALLY supplies this attribute. The IPP object
MUST support this attribute. It is a set of attribute names
and/or attribute group names in whose values the requester is
interested. If the client omits this attribute, the IPP object
MUST respond as if this attribute had been supplied with a value
of 'all'.
3.3.4.2 Get-Job-Attributes Response
The Printer object returns the following sets of attributes as part
of the Get-Job-Attributes Response:
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Group 1: Operation Attributes
Status Message:
In addition to the REQUIRED status code returned in every
response, the response OPTIONALLY includes a "status-message"
(text) operation attribute as described in sections 14 and
3.1.6.
Natural Language and Character Set:
The "attributes-charset" and "attributes-natural-language"
attributes as described in section 3.1.4.2. The "attributes-
natural-language" MAY be the natural language of the Job object,
rather than the one requested.
Group 2: Unsupported Attributes
This is a set of Operation attributes supplied by the client (in
the request) that are not supported by the Printer object or
that conflict with one another (see sections 3.2.1.2 and the
Implementer's Guide [ipp-iig]). The response NEED NOT contain
the "requested-attributes" operation attribute with any supplied
values (attribute keywords) that were requested by the client
but are not supported by the IPP object. If the Printer object
is not returning any Unsupported Attributes in the response, the
Printer object SHOULD omit Group 2 rather than sending an empty
group. However, a client MUST be able to accept an empty group.
Group 3: Job Object Attributes
This is the set of requested attributes and their current
values. The IPP object ignores (does not respond with) any
requested attribute or value which is not supported or which is
restricted by the security policy in force, including whether
the requesting user is the user that submitted the job (job
originating user) or not (see section 8). However, the IPP
object MUST respond with the 'unknown' value for any supported
attribute (including all RED butes) for which the IPP object
does not know the value, s it would violate the security policy.
See the description e "out-of-band" values in the beginning of
Section 4.1.
4. Object Attributes
This section describes the attributes with their corresponding
attribute syntaxes and values that are part of the IPP model. The
sections below show the objects and their associated attributes which
are included within the scope of this protocol. Many of these
attributes are derived from other relevant specifications:
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- Document Printing Application (DPA) [ISO10175]
- RFC 1759 Printer MIB [RFC1759]
Each attribute is uniquely identified in this document using a
"keyword" (see section 12.2.1) which is the name of the attribute.
The keyword is included in the section header describing that
attribute.
Note: Not only are keywords used to identify attributes, but one of
the attribute syntaxes described below is "keyword" so that some
attributes have keyword values. Therefore, these attributes are
defined as having an attribute syntax that is a set of keywords.
4.1 Attribute Syntaxes
This section defines the basic attribute syntax types that all clients
and IPP objects MUST be able to accept in responses and accept in
requests, respectively. Each attribute description in sections 3 and
4 includes the name of attribute syntax(es) in the heading (in
parentheses). A conforming implementation of an attribute MUST
include the semantics of the attribute syntax(es) so identified.
Section 6.3 describes how the protocol can be extended with new
attribute syntaxes.
The attribute syntaxes are specified in the following sub-sections,
where the sub-section heading is the keyword name of the attribute
syntax inside the single quotes. In operation requests and responses
each attribute value MUST be represented as one of the attribute
syntaxes specified in the sub-section heading for the attribute. In
addition, the value of an attribute in a response (but not in a
request) MAY be one of the "out-of-band" values. Standard
"out-of-band" values are:
'unknown': The attribute is supported by the IPP object, but the
value is unknown to the IPP object for some reason.
'unsupported': The attribute is unsupported by the IPP object. This
value MUST be returned only as the value of an attribute in the
Unsupported Attributes Group.
'no-value': The attribute is supported by the Printer object, but
the system administrator has not yet configured a value.
The Encoding and Transport specification [RFC2565] defines mechanisms
for passing "out-of-band" values. All attributes in a request MUST
have one or more values as defined in Sections 4.2 to 4.4. Thus
clients MUST NOT supply attributes with "out-of-band" values. All
attribute in a response MUST have one or more values as defined in
Sections 4.2 to 4.4 or a single "out-of-band" value.
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Most attributes are defined to have a single attribute syntax.
However, a few attributes (e.g., "job-sheet", "media", "job-hold-
until") are defined to have several attribute syntaxes, depending on
the value. These multiple attribute syntaxes are separated by the
"|" character in the sub-section heading to indicate the choice.
Since each value MUST be tagged as to its attribute syntax in the
protocol, a single-valued attribute instance may have any one of its
attribute syntaxes and a multi-valued attribute instance may have a
mixture of its defined attribute syntaxes.
4.1.1 'text'
A text attribute is an attribute whose value is a sequence of zero or
more characters encoded in a maximum of 1023 ('MAX') octets. MAX is
the maximum length for each value of any text attribute. However, if
an attribute will always contain values whose maximum length is much
less than MAX, the definition of that attribute will include a
qualifier that defines the maximum length for values of that
attribute. For example: the "printer-location" attribute is
specified as "printer-location (text(127))". In this case, text
values for "printer-location" MUST NOT exceed 127 octets; if supplied
with a longer text string via some external interface (other than the
protocol), implementations are free to truncate to this shorter
length limitation.
In this specification, all text attributes are defined using the '
text' syntax. However, 'text' is used only for brevity; the formal
interpretation of 'text' is: 'textWithoutLanguage |
textWithLanguage'. That is, for any attribute defined in this
specification using the 'text' attribute syntax, all IPP objects and
clients MUST support both the 'textWithoutLanguage' and '
textWithLanguage' attribute syntaxes. However, in actual usage and
protocol execution, objects and clients accept and return only one of
the two syntax per attribute. The syntax 'text' never appears "on-
the-wire".
Both 'textWithoutLanguage' and 'textWithLanguage' are needed to
support the real world needs of interoperability between sites and
systems that use different natural languages as the basis for human
communication. Generally, one natural language applies to all text
attributes in a given request or response. The language is indicated
by the "attributes-natural-language" operation attribute defined in
section 3.1.4 or "attributes-natural-language" job attribute defined
in section 4.3.24, and there is no need to identify the natural
language for each text string on a value-by-value basis. In these
cases, the attribute syntax 'textWithoutLanguage' is used for text
attributes. In other cases, the client needs to supply or the
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Printer object needs to return a text value in a natural language
that is different from the rest of the text values in the request or
response. In these cases, the client or Printer object uses the
attribute syntax 'textWithLanguage' for text attributes (this is the
Natural Language Override mechanism described in section 3.1.4).
The 'textWithoutLanguage' and 'textWithLanguage' attribute syntaxes
are described in more detail in the following sections.
4.1.1.1 'textWithoutLanguage'
The 'textWithoutLanguage' syntax indicates a value that is sequence
of zero or more characters. Text strings are encoded using the rules
of some charset. The Printer object MUST support the UTF-8 charset
[RFC2279] and MAY support additional charsets to represent 'text'
values, provided that the charsets are registered with IANA [IANA-
CS]. See Section 4.1.7 for the specification of the 'charset'
attribute syntax, including restricted semantics and examples of
charsets.
4.1.1.2 'textWithLanguage'
The 'textWithLanguage' attribute syntax is a compound attribute
syntax consisting of two parts: a 'textWithoutLanguage' part plus an
additional 'naturalLanguage' (see section 4.1.8) part that overrides
the natural language in force. The 'naturalLanguage' part explicitly
identifies the natural language that applies to the text part of that
value and that value alone. For any give text attribute, the '
textWithoutLanguage' part is limited to the maximum length defined
for that attribute, but the 'naturalLanguage' part is always limited
to 63 octets. Using the 'textWithLanguage' attribute syntax rather
than the normal 'textWithoutLanguage' syntax is the so-called Natural
Language Override mechanism and MUST be supported by all IPP objects
and clients.
If the attribute is multi-valued (1setOf text), then the '
textWithLanguage' attribute syntax MUST be used to explicitly specify
each attribute value whose natural language needs to be overridden.
Other values in a multi-valued 'text' attribute in a request or a
response revert to the natural language of the operation attribute.
In a create request, the Printer object MUST accept and store with
the Job object any natural language in the "attributes-natural-
language" operation attribute, whether the Printer object supports
that natural language or not. Furthermore, the Printer object MUST
accept and store any 'textWithLanguage' attribute value, whether the
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Printer object supports that natural language or not. These
requirements are independent of the value of the "ipp-attribute-
fidelity" operation attribute that the client MAY supply.
Example: If the client supplies the "attributes-natural-language"
operation attribute with the value: 'en' indicating English, but the
value of the "job-name" attribute is in French, the client MUST use
the 'textWithLanguage' attribute syntax with the following two
values:
'fr': Natural Language Override indicating French
'Rapport Mensuel': the job name in French
See the Encoding and Transport document [RFC2565] for a detailed
example of the 'textWithLanguage' attribute syntax.
4.1.2 'name'
This syntax type is used for user-friendly strings, such as a Printer
name, that, for humans, are more meaningful than identifiers. Names
are never translated from one natural language to another. The '
name' attribute syntax is essentially the same as 'text', including
the REQUIRED support of UTF-8 except that the sequence of characters
is limited so that its encoded form MUST NOT exceed 255 (MAX) octets.
Also like 'text', 'name' is really an abbreviated notation for either
'nameWithoutLanguage' or 'nameWithLanguage'. That is, all IPP
objects and clients MUST support both the 'nameWithoutLanguage' and '
nameWithLanguage' attribute syntaxes. However, in actual usage and
protocol execution, objects and clients accept and return only one of
the two syntax per attribute. The syntax 'name' never appears "on-
the-wire".
Note: Only the 'text' and 'name' attribute syntaxes permit the
Natural Language Override mechanism.
Some attributes are defined as 'type3 keyword | name'. These
attributes support values that are either type3 keywords or names.
This dual-syntax mechanism enables a site administrator to extend
these attributes to legally include values that are locally defined
by the site administrator. Such names are not registered with IANA.
4.1.2.1 'nameWithoutLanguage'
The 'nameWithoutLanguage' syntax indicates a value that is sequence
of zero or more characters so that its encoded form does not exceed
MAX octets.
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4.1.2.2 'nameWithLanguage'
The 'nameWithLanguage' attribute syntax is a compound attribute
syntax consisting of two parts: a 'nameWithoutLanguage' part plus an
additional 'naturalLanguage' (see section 4.1.8) part that overrides
the natural language in force. The 'naturalLanguage' part explicitly
identifies the natural language that applies to that name value and
that name value alone.
The 'nameWithLanguage' attribute syntax behaves the same as the '
textWithLanguage' syntax. If a name is in a language that is
different than the rest of the object or operation, then this '
nameWithLanguage' syntax is used rather than the generic '
nameWithoutLanguage' syntax.
Example: If the client supplies the "attributes-natural-language"
operation attribute with the value: 'en' indicating English, but the
"printer-name" attribute is in German, the client MUST use the '
nameWithLanguage' attribute syntax as follows:
'de': Natural Language Override indicating German
'Farbdrucker': the Printer name in German
4.1.2.3 Matching 'name' attribute values
For purposes of matching two 'name' attribute values for equality,
such as in job validation (where a client-supplied value for
attribute "xxx" is checked to see if the value is among the values of
the Printer object's corresponding "xxx-supported" attribute), the
following match rules apply:
1. 'keyword' values never match 'name' values.
2. 'name' (nameWithoutLanguage and nameWithLanguage) values
match if (1) the name parts match and (2) the Associated
Natural-Language parts (see section 3.1.4.1) match. The
matching rules are:
a. the name parts match if the two names are identical
character by character, except it is RECOMMENDED that case
be ignored. For example: 'Ajax-letter-head-white' MUST
match 'Ajax-letter-head-white' and SHOULD match 'ajax-
letter-head-white' and 'AJAX-LETTER-HEAD-WHITE'.
b. the Associated Natural-Language parts match if the
shorter of the two meets the syntactic requirements of RFC
1766 [RFC1766] and matches byte for byte with the longer.
For example, 'en' matches 'en', 'en-us' and 'en-gb', but
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matches neither 'fr' nor 'e'.
4.1.3 'keyword'
The 'keyword' attribute syntax is a sequence of characters, length: 1
to 255, containing only the US-ASCII [ASCII] encoded values for
lowercase letters ("a" - "z"), digits ("0" - "9"), hyphen ("-"), dot
("."), and underscore ("_"). The first character MUST be a lowercase
letter. Furthermore, keywords MUST be in U.S. English.
This syntax type is used for enumerating semantic identifiers of
entities in the abstract protocol, i.e., entities identified in this
document. Keywords are used as attribute names or values of
attributes. Unlike 'text' and 'name' attribute values, 'keyword'
values MUST NOT use the Natural Language Override mechanism, since
they MUST always be US-ASCII and U.S. English.
Keywords are for use in the protocol. A user interface will likely
provide a mapping between protocol keywords and displayable user-
friendly words and phrases which are localized to the natural
language of the user. While the keywords specified in this document
MAY be displayed to users whose natural language is U.S. English,
they MAY be mapped to other U.S. English words for U.S. English
users, since the user interface is outside the scope of this
document.
In the definition for each attribute of this syntax type, the full
set of defined keyword values for that attribute are listed.
When a keyword is used to represent an attribute (its name), it MUST
be unique within the full scope of all IPP objects and attributes.
When a keyword is used to represent a value of an attribute, it MUST
be unique just within the scope of that attribute. That is, the same
keyword MUST NOT be used for two different values within the same
attribute to mean two different semantic ideas. However, the same
keyword MAY be used across two or more attributes, representing
different semantic ideas for each attribute. Section 6.1 describes
how the protocol can be extended with new keyword values. Examples
of attribute name keywords:
"job-name"
"attributes-charset"
Note: This document uses "type1", "type2", and "type3" prefixes to
the "keyword" basic syntax to indicate different levels of review for
extensions (see section 6.1).
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4.1.4 'enum'
The 'enum' attribute syntax is an enumerated integer value that is in
the range from 1 to 2**31 - 1 (MAX). Each value has an associated '
keyword' name. In the definition for each attribute of this syntax
type, the full set of possible values for that attribute are listed.
This syntax type is used for attributes for which there are enum
values assigned by other standards, such as SNMP MIBs. A number of
attribute enum values in this specification are also used for
corresponding attributes in other standards [RFC1759]. This syntax
type is not used for attributes to which the system administrator may
assign values. Section 6.1 describes how the protocol can be
extended with new enum values.
Enum values are for use in the protocol. A user interface will
provide a mapping between protocol enum values and displayable user-
friendly words and phrases which are localized to the natural
language of the user. While the enum symbols specified in this
document MAY be displayed to users whose natural language is U.S.
English, they MAY be mapped to other U.S. English words for U.S.
English users, since the user interface is outside the scope of this
document.
Note: SNMP MIBs use '2' for 'unknown' which corresponds to the IPP
"out-of-band" value 'unknown'. See the description of the "out-of-
band" values at the beginning of Section 4.1. Therefore, attributes
of type 'enum' start at '3'.
Note: This document uses "type1", "type2", and "type3" prefixes to
the "enum" basic syntax to indicate different levels of review for
extensions (see section 6.1).
4.1.5 'uri'
The 'uri' attribute syntax is any valid Uniform Resource Identifier
or URI [RFC2396]. Most often, URIs are simply Uniform Resource
Locators or URLs. The maximum length of URIs used as values of IPP
attributes is 1023 octets. Although most other IPP attribute syntax
types allow for only lower-cased values, this attribute syntax type
conforms to the case-sensitive and case-insensitive rules specified
in [RFC2396].
4.1.6 'uriScheme'
The 'uriScheme' attribute syntax is a sequence of characters
representing a URI scheme according to RFC 2396 [RFC2396]. Though
RFC 2396 requires that the values be case-insensitive, IPP requires
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all lower case values in IPP attributes to simplify comparing by IPP
clients and Printer objects. Standard values for this syntax type
are the following keywords:
'http': for HTTP schemed URIs (e.g., "http:...")
'https': for use with HTTPS schemed URIs (e.g., "https:...")
(not on IETF standards track)
'ftp': for FTP schemed URIs (e.g., "ftp:...")
'mailto': for SMTP schemed URIs (e.g., "mailto:...")
'file': for file schemed URIs (e.g., "file:...")
A Printer object MAY support any URI 'scheme' that has been
registered with IANA [IANA-MT]. The maximum length of URI 'scheme'
values used to represent IPP attribute values is 63 octets.
4.1.7 'charset'
The 'charset' attribute syntax is a standard identifier for a
charset. A charset is a coded character set and encoding scheme.
Charsets are used for labeling certain document contents and 'text'
and 'name' attribute values. The syntax and semantics of this
attribute syntax are specified in RFC 2046 [RFC2046] and contained in
the IANA character-set Registry [IANA-CS] according to the IANA
procedures [RFC2278]. Though RFC 2046 requires that the values be
case-insensitive US-ASCII, IPP requires all lower case values in IPP
attributes to simplify comparing by IPP clients and Printer objects.
When a character-set in the IANA registry has more than one name
(alias), the name labeled as "(preferred MIME name)", if present,
MUST be used.
The maximum length of 'charset' values used to represent IPP
attribute values is 63 octets.
Some examples are:
'utf-8': ISO 10646 Universal Multiple-Octet Coded Character Set
(UCS) represented as the UTF-8 [RFC2279] transfer encoding
scheme in which US-ASCII is a subset charset.
'us-ascii': 7-bit American Standard Code for Information
Interchange (ASCII), ANSI X3.4-1986 [ASCII]. That standard
defines US-ASCII, but RFC 2045 [RFC2045] eliminates most of the
control characters from conformant usage in MIME and IPP.
'iso-8859-1': 8-bit One-Byte Coded Character Set, Latin Alphabet
Nr 1 [ISO8859-1]. That standard defines a coded character set
that is used by Latin languages in the Western Hemisphere and
Western Europe. US-ASCII is a subset charset.
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'iso-10646-ucs-2': ISO 10646 Universal Multiple-Octet Coded
Character Set (UCS) represented as two octets (UCS-2), with the
high order octet of each pair coming first (so-called Big Endian
integer).
Some attribute descriptions MAY place additional requirements on
charset values that may be used, such as REQUIRED values that MUST be
supported or additional restrictions, such as requiring that the
charset have US-ASCII as a subset charset.
4.1.8 'naturalLanguage'
The 'naturalLanguage' attribute syntax is a standard identifier for a
natural language and optionally a country. The values for this
syntax type are defined by RFC 1766 [RFC1766]. Though RFC 1766
requires that the values be case-insensitive US-ASCII, IPP requires
all lower case to simplify comparing by IPP clients and Printer
objects. Examples include:
'en': for English
'en-us': for US English
'fr': for French
'de': for German
The maximum length of 'naturalLanguage' values used to represent IPP
attribute values is 63 octets.
4.1.9 'mimeMediaType'
The 'mimeMediaType' attribute syntax is the Internet Media Type
(sometimes called MIME type) as defined by RFC 2046 [RFC2046] and
registered according to the procedures of RFC 2048 [RFC2048] for
identifying a document format. The value MAY include a charset
parameter, depending on the specification of the Media Type in the
IANA Registry [IANA-MT]. Although most other IPP syntax types allow
for only lower-cased values, this syntax type allows for mixed-case
values which are case-insensitive.
Examples are:
'text/html': An HTML document
'text/plain': A plain text document in US-ASCII (RFC 2046 indicates
that in the absence of the charset parameter MUST mean US-ASCII
rather than simply unspecified) [RFC2046].
'text/plain; charset=US-ASCII': A plain text document in US-ASCII
[52, 56].
'text/plain; charset=ISO-8859-1': A plain text document in ISO
8859-1 (Latin 1) [ISO8859-1].
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'text/plain; charset=utf-8': A plain text document in ISO 10646
represented as UTF-8 [RFC2279]
'text/plain, charset=iso-10646-ucs-2': A plain text document in
ISO 10646 represented in two octets (UCS-2) [ISO10646-1]
'application/postscript': A PostScript document [RFC2046]
'application/vnd.hp-PCL': A PCL document [IANA-MT] (charset escape
sequence embedded in the document data)
'application/octet-stream': Auto-sense - see below
One special type is 'application/octet-stream'. If the Printer
object supports this value, the Printer object MUST be capable of
auto-sensing the format of the document data. If the Printer
object's default value attribute "document-format-default" is set to
'application/octet-stream', the Printer object not only supports
auto-sensing of the document format, but will depend on the result of
applying its auto-sensing when the client does not supply the
"document-format" attribute. If the client supplies a document
format value, the Printer MUST rely on the supplied attribute, rather
than trust its auto-sensing algorithm. To summarize:
1. If the client does not supply a document format value, the
Printer MUST rely on its default value setting (which may be '
application/octet-stream' indicating an auto-sensing mechanism).
2. If the client supplies a value other than 'application/octet-
stream', the client is supplying valid information about the
format of the document data and the Printer object MUST trust
the client supplied value more than the outcome of applying an
automatic format detection mechanism. For example, the client
may be requesting the printing of a PostScript file as a '
text/plain' document. The Printer object MUST print a text
representation of the PostScript commands rather than interpret
the stream of PostScript commands and print the result.
3. If the client supplies a value of 'application/octet-stream',
the client is indicating that the Printer object MUST use its
auto-sensing mechanism on the client supplied document data
whether auto-sensing is the Printer object's default or not.
Note: Since the auto-sensing algorithm is probabilistic, if the
client requests both auto-sensing ("document-format" set to '
application/octet-stream') and true fidelity ("ipp-attribute-
fidelity" set to 'true'), the Printer object might not be able to
guarantee exactly what the end user intended (the auto-sensing
algorithm might mistake one document format for another ), but it is
able to guarantee that its auto-sensing mechanism be used.
The maximum length of a 'mimeMediaType' value to represent IPP
attribute values is 255 octets.
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4.1.10 'octetString'
The 'octetString' attribute syntax is a sequence of octets encoded in
a maximum of 1023 octets which is indicated in sub-section headers
using the notation: octetString(MAX). This syntax type is used for
opaque data.
4.1.11 'boolean'
The 'boolean' attribute syntax has only two values: 'true' and '
false'.
4.1.12 'integer'
The 'integer' attribute syntax is an integer value that is in the
range from -2**31 (MIN) to 2**31 - 1 (MAX). Each individual
attribute may specify the range constraint explicitly in sub-section
headers if the range is different from the full range of possible
integer values. For example: job-priority (integer(1:100)) for the
"job-priority" attribute. However, the enforcement of that
additional constraint is up to the IPP objects, not the protocol.
4.1.13 'rangeOfInteger'
The 'rangeOfInteger' attribute syntax is an ordered pair of integers
that defines an inclusive range of integer values. The first integer
specifies the lower bound and the second specifies the upper bound.
If a range constraint is specified in the header description for an
attribute in this document whose attribute syntax is 'rangeOfInteger'
(i.e., 'X:Y' indicating X as a minimum value and Y as a maximum
value), then the constraint applies to both integers.
4.1.14 'dateTime'
The 'dateTime' attribute syntax is a standard, fixed length, 11 octet
representation of the "DateAndTime" syntax as defined in RFC 2579
[RFC2579]. RFC 2579 also identifies an 8 octet representation of a
"DateAndTime" value, but IPP objects MUST use the 11 octet
representation. A user interface will provide a mapping between
protocol dateTime values and displayable user-friendly words or
presentation values and phrases which are localized to the natural
language and date format of the user.
4.1.15 'resolution'
The 'resolution' attribute syntax specifies a two-dimensional
resolution in the indicated units. It consists of 3 values: a cross
feed direction resolution (positive integer value), a feed direction
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resolution (positive integer value), and a units value. The
semantics of these three components are taken from the Printer MIB
[RFC1759] suggested values. That is, the cross feed direction
component resolution component is the same as the
prtMarkerAddressabilityXFeedDir object in the Printer MIB, the feed
direction component resolution component is the same as the
prtMarkerAddressabilityFeedDir in the Printer MIB, and the units
component is the same as the prtMarkerAddressabilityUnit object in
the Printer MIB (namely, '3' indicates dots per inch and '4'
indicates dots per centimeter). All three values MUST be present
even if the first two values are the same. Example: '300', '600', '
3' indicates a 300 dpi cross-feed direction resolution, a 600 dpi
feed direction resolution, since a '3' indicates dots per inch (dpi).
4.1.16 '1setOf X'
The '1setOf X' attribute syntax is 1 or more values of attribute
syntax type X. This syntax type is used for multi-valued attributes.
The syntax type is called '1setOf' rather than just 'setOf' as a
reminder that the set of values MUST NOT be empty (i.e., a set of
size 0). Sets are normally unordered. However each attribute
description of this type may specify that the values MUST be in a
certain order for that attribute.
4.2 Job Template Attributes
Job Template attributes describe job processing behavior. Support
for Job Template attributes by a Printer object is OPTIONAL (see
section 13.2.3 for a description of support for OPTIONAL attributes).
Also, clients OPTIONALLY supply Job Template attributes in create
requests.
Job Template attributes conform to the following rules. For each Job
Template attribute called "xxx":
1. If the Printer object supports "xxx" then it MUST support both a
"xxx-default" attribute (unless there is a "No" in the table
below) and a "xxx-supported" attribute. If the Printer object
doesn't support "xxx", then it MUST support neither an "xxx-
default" attribute nor an "xxx-supported" attribute, and it MUST
treat an attribute "xxx" supplied by a client as unsupported.
An attribute "xxx" may be supported for some document formats
and not supported for other document formats. For example, it
is expected that a Printer object would only support
"orientation-requested" for some document formats (such as '
text/plain' or 'text/html') but not others (such as '
application/postscript').
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2. "xxx" is OPTIONALLY supplied by the client in a create request.
If "xxx" is supplied, the client is indicating a desired job
processing behavior for this Job. When "xxx" is not supplied,
the client is indicating that the Printer object apply its
default job processing behavior at job processing time if the
document content does not contain an embedded instruction
indicating an xxx-related behavior.
Note: Since an administrator MAY change the default value
attribute after a Job object has been submitted but before it
has been processed, the default value used by the Printer object
at job processing time may be different that the default value
in effect at job submission time.
3. The "xxx-supported" attribute is a Printer object attribute that
describes which job processing behaviors are supported by that
Printer object. A client can query the Printer object to find
out what xxx-related behaviors are supported by inspecting the
returned values of the "xxx-supported" attribute.
Note: The "xxx" in each "xxx-supported" attribute name is
singular, even though an "xxx-supported" attribute usually has
more than one value, such as "job-sheet-supported", unless the
"xxx" Job Template attribute is plural, such as "finishings" or
"sides". In such cases the "xxx-supported" attribute names are:
"finishings-supported" and "sides-supported".
4. The "xxx-default" default value attribute describes what will be
done at job processing time when no other job processing
information is supplied by the client (either explicitly as an
IPP attribute in the create request or implicitly as an embedded
instruction within the document data).
If an application wishes to present an end user with a list of
supported values from which to choose, the application SHOULD query
the Printer object for its supported value attributes. The
application SHOULD also query the default value attributes. If the
application then limits selectable values to only those value that
are supported, the application can guarantee that the values supplied
by the client in the create request all fall within the set of
supported values at the Printer. When querying the Printer, the
client MAY enumerate each attribute by name in the Get-Printer-
Attributes Request, or the client MAY just name the "job-template"
group in order to get the complete set of supported attributes (both
supported and default attributes).
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The "finishings" attribute is an example of a Job Template attribute.
It can take on a set of values such as 'staple', 'punch', and/or '
cover'. A client can query the Printer object for the "finishings-
supported" attribute and the "finishings-default" attribute. The
supported attribute contains a set of supported values. The default
value attribute contains the finishing value(s) that will be used for
a new Job if the client does not supply a "finishings" attribute in
the create request and the document data does not contain any
corresponding finishing instructions. If the client does supply the
"finishings" attribute in the create request, the IPP object
validates the value or values to make sure that they are a subset of
the supported values identified in the Printer object's "finishings-
supported" attribute. See section 3.2.1.2.
The table below summarizes the names and relationships for all Job
Template attributes. The first column of the table (labeled "Job
Attribute") shows the name and syntax for each Job Template attribute
in the Job object. These are the attributes that can optionally be
supplied by the client in a create request. The last two columns
(labeled "Printer: Default Value Attribute" and "Printer: Supported
Values Attribute") shows the name and syntax for each Job Template
attribute in the Printer object (the default value attribute and the
supported values attribute). A "No" in the table means the Printer
MUST NOT support the attribute (that is, the attribute is simply not
applicable). For brevity in the table, the 'text' and 'name' entries
do not show the maximum length for each attribute.
+===================+======================+======================+
| Job Attribute |Printer: Default Value| Printer: Supported |
| | Attribute | Values Attribute |
+===================+======================+======================+
| job-priority | job-priority-default |job-priority-supported|
| (integer 1:100) | (integer 1:100) |(integer 1:100) |
+-------------------+----------------------+----------------------+
| job-hold-until | job-hold-until- |job-hold-until- |
| (type3 keyword | | default | supported |
| name) | (type3 keyword | |(1setOf |
| | name) | type3 keyword | name)|
+-------------------+----------------------+----------------------+
| job-sheets | job-sheets-default |job-sheets-supported |
| (type3 keyword | | (type3 keyword | |(1setOf |
| name) | name) | type3 keyword | name)|
+-------------------+----------------------+----------------------+
|multiple-document- |multiple-document- |multiple-document- |
| handling | handling-default |handling-supported |
| (type2 keyword) | (type2 keyword) |(1setOf type2 keyword)|
+-------------------+----------------------+----------------------+
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+===================+======================+======================+
| Job Attribute |Printer: Default Value| Printer: Supported |
| | Attribute | Values Attribute |
+===================+======================+======================+
| copies | copies-default | copies-supported |
| (integer (1:MAX)) | (integer (1:MAX)) | (rangeOfInteger |
| | | (1:MAX)) |
+-------------------+----------------------+----------------------+
| finishings | finishings-default | finishings-supported |
|(1setOf type2 enum)|(1setOf type2 enum) |(1setOf type2 enum) |
+-------------------+----------------------+----------------------+
| page-ranges | No | page-ranges- |
| (1setOf | | supported (boolean) |
| rangeOfInteger | | |
| (1:MAX)) | | |
+-------------------+----------------------+----------------------+
| sides | sides-default | sides-supported |
| (type2 keyword) | (type2 keyword) |(1setOf type2 keyword)|
+-------------------+----------------------+----------------------+
| number-up | number-up-default | number-up-supported |
| (integer (1:MAX)) | (integer (1:MAX)) |(1setOf integer |
| | | (1:MAX) | |
| | | rangeOfInteger |
| | | (1:MAX)) |
+-------------------+----------------------+----------------------+
| orientation- |orientation-requested-|orientation-requested-|
| requested | default | supported |
| (type2 enum) | (type2 enum) | (1setOf type2 enum) |
+-------------------+----------------------+----------------------+
| media | media-default | media-supported |
| (type3 keyword | | (type3 keyword | |(1setOf |
| name) | name) | type3 keyword | name)|
| | | |
| | | media-ready |
| | |(1setOf |
| | | type3 keyword | name)|
+-------------------+----------------------+----------------------+
| printer-resolution| printer-resolution- | printer-resolution- |
| (resolution) | default | supported |
| | (resolution) |(1setOf resolution) |
+-------------------+----------------------+----------------------+
| print-quality | print-quality-default| print-quality- |
| (type2 enum) | (type2 enum) | supported |
| | |(1setOf type2 enum) |
+-------------------+----------------------+----------------------+
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4.2.1 job-priority (integer(1:100))
This attribute specifies a priority for scheduling the Job. A higher
value specifies a higher priority. The value 1 indicates the lowest
possible priority. The value 100 indicates the highest possible
priority. Among those jobs that are ready to print, a Printer MUST
print all jobs with a priority value of n before printing those with
a priority value of n-1 for all n.
If the Printer object supports this attribute, it MUST always support
the full range from 1 to 100. No administrative restrictions are
permitted. This way an end-user can always make full use of the
entire range with any Printer object. If privileged jobs are
implemented outside IPP/1.0, they MUST have priorities higher than
100, rather than restricting the range available to end-users.
If the client does not supply this attribute and this attribute is
supported by the Printer object, the Printer object MUST use the
value of the Printer object's "job-priority-default" at job
submission time (unlike most Job Template attributes that are used if
necessary at job processing time).
The syntax for the "job-priority-supported" is also integer(1:100).
This single integer value indicates the number of priority levels
supported. The Printer object MUST take the value supplied by the
client and map it to the closest integer in a sequence of n integers
values that are evenly distributed over the range from 1 to 100 using
the formula:
roundToNearestInt((100x+50)/n)
where n is the value of "job-priority-supported" and x ranges from 0
through n-1.
For example, if n=1 the sequence of values is 50; if n=2, the
sequence of values is: 25 and 75; if n = 3, the sequence of values
is: 17, 50 and 83; if n = 10, the sequence of values is: 5, 15, 25,
35, 45, 55, 65, 75, 85, and 95; if n = 100, the sequence of values
is: 1, 2, 3, . 100.
If the value of the Printer object's "job-priority-supported" is 10
and the client supplies values in the range 1 to 10, the Printer
object maps them to 5, in the range 11 to 20, the Printer object maps
them to 15, etc.
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4.2.2 job-hold-until (type3 keyword | name (MAX))
This attribute specifies the named time period during which the Job
MUST become a candidate for printing.
Standard keyword values for named time periods are:
'no-hold': immediately, if there are not other reasons to hold the
job
'day-time': during the day
'evening': evening
'night': night
'weekend': weekend
'second-shift': second-shift (after close of business)
'third-shift': third-shift (after midnight)
An administrator MUST associate allowable print times with a named
time period (by means outside IPP/1.0). An administrator is
encouraged to pick names that suggest the type of time period. An
administrator MAY define additional values using the 'name' or '
keyword' attribute syntax, depending on implementation.
If the value of this attribute specifies a time period that is in the
future, the Printer MUST add the 'job-hold-until-specified' value to
the job's "job-state-reasons" attribute, move the job to the '
pending-held' state, and MUST NOT schedule the job for printing until
the specified time-period arrives. When the specified time period
arrives, the Printer MUST remove the 'job-hold-until-specified' value
from the job's "job-state-reason" attribute and, if there are no
other job state reasons that keep the job in the 'pending-held'
state, the Printer MUST consider the job as a candidate for
processing by moving the job to the 'pending' state.
If this job attribute value is the named value 'no-hold', or the
specified time period has already started, the job MUST be a
candidate for processing immediately.
If the client does not supply this attribute and this attribute is
supported by the Printer object, the Printer object MUST use the
value of the Printer object's "job-hold-until-default" at job
submission time (unlike most Job Template attributes that are used if
necessary at job processing time).
4.2.3 job-sheets (type3 keyword | name(MAX))
This attribute determines which job start/end sheet(s), if any, MUST
be printed with a job.
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Standard keyword values are:
'none': no job sheet is printed
'standard': one or more site specific standard job sheets are
printed, e.g. a single start sheet or both start and end sheet
is printed
An administrator MAY define additional values using the 'name' or '
keyword' attribute syntax, depending on implementation.
Note: The effect of this attribute on jobs with multiple documents
MAY be affected by the "multiple-document-handling" job attribute
(section 4.2.4), depending on the job sheet semantics.
4.2.4 multiple-document-handling (type2 keyword)
This attribute is relevant only if a job consists of two or more
documents. The attribute controls finishing operations and the
placement of one or more print-stream pages into impressions and onto
media sheets. When the value of the "copies" attribute exceeds 1, it
also controls the order in which the copies that result from
processing the documents are produced. For the purposes of this
explanations, if "a" represents an instance of document data, then
the result of processing the data in document "a" is a sequence of
media sheets represented by "a(*)".
Standard keyword values are:
'single-document': If a Job object has multiple documents, say, the
document data is called a and b, then the result of processing
all the document data (a and then b) MUST be treated as a single
sequence of media sheets for finishing operations; that is,
finishing would be performed on the concatenation of the
sequences a(*),b(*). The Printer object MUST NOT force the data
in each document instance to be formatted onto a new print-
stream page, nor to start a new impression on a new media sheet.
If more than one copy is made, the ordering of the sets of media
sheets resulting from processing the document data MUST be a(*),
b(*), a(*), b(*), ..., and the Printer object MUST force each
copy (a(*),b(*)) to start on a new media sheet.
'separate-documents-uncollated-copies': If a Job object has
multiple documents, say, the document data is called a and b,
then the result of processing the data in each document instance
MUST be treated as a single sequence of media sheets for
finishing operations; that is, the sets a(*) and b(*) would each
be finished separately. The Printer object MUST force each copy
of the result of processing the data in a single document to
start on a new media sheet. If more than one copy is made, the
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ordering of the sets of media sheets resulting from processing
the document data MUST be a(*), a(*), ..., b(*), b(*) ... .
'separate-documents-collated-copies': If a Job object has multiple
documents, say, the document data is called a and b, then the
result of processing the data in each document instance MUST be
treated as a single sequence of media sheets for finishing
operations; that is, the sets a(*) and b(*) would each be
finished separately. The Printer object MUST force each copy of
the result of processing the data in a single document to start
on a new media sheet. If more than one copy is made, the
ordering of the sets of media sheets resulting from processing
the document data MUST be a(*), b(*), a(*), b(*), ... .
'single-document-new-sheet': Same as 'single-document', except
that the Printer object MUST ensure that the first impression of
each document instance in the job is placed on a new media
sheet. This value allows multiple documents to be stapled
together with a single staple where each document starts on a
new sheet.
The 'single-document' value is the same as 'separate-documents-
collated-copies' with respect to ordering of print-stream pages, but
not media sheet generation, since 'single-document' will put the
first page of the next document on the back side of a sheet if an odd
number of pages have been produced so far for the job, while '
separate-documents-collated-copies' always forces the next document
or document copy on to a new sheet. In addition, if the "finishings"
attribute specifies 'staple', then with 'single-document', documents
a and b are stapled together as a single document with no regard to
new sheets, with 'single-document-new-sheet', documents a and b are
stapled together as a single document, but document b starts on a new
sheet, but with 'separate-documents-uncollated-copies' and '
separate-documents-collated-copies', documents a and b are stapled
separately.
Note: None of these values provide means to produce uncollated sheets
within a document, i.e., where multiple copies of sheet n are
produced before sheet n+1 of the same document.
The relationship of this attribute and the other attributes that
control document processing is described in section 15.3.
4.2.5 copies (integer(1:MAX))
This attribute specifies the number of copies to be printed.
On many devices the supported number of collated copies will be
limited by the number of physical output bins on the device, and may
be different from the number of uncollated copies which can be
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supported.
Note: The effect of this attribute on jobs with multiple documents is
controlled by the "multiple-document-handling" job attribute (section
4.2.4) and the relationship of this attribute and the other
attributes that control document processing is described in section
15.3.
4.2.6 finishings (1setOf type2 enum)
This attribute identifies the finishing operations that the Printer
uses for each copy of each printed document in the Job. For Jobs with
multiple documents, the "multiple-document-handling" attribute
determines what constitutes a "copy" for purposes of finishing.
Standard enum values are:
Value Symbolic Name and Description
'3' 'none': Perform no finishing
'4' 'staple': Bind the document(s) with one or more staples.
The exact number and placement of the staples is
site-defined.
'5' 'punch': This value indicates that holes are required in
the finished document. The exact number and placement
of the holes is site-defined The punch specification
MAY be satisfied (in a site- and implementation-
specific manner) either by drilling/punching, or by
substituting pre-drilled media.
'6' 'cover': This value is specified when it is desired to
select a non-printed (or pre-printed) cover for the
document. This does not supplant the specification of
a printed cover (on cover stock medium) by the
document itself.
'7' 'bind': This value indicates that a binding is to be
applied to the document; the type and placement of the
binding is site-defined."
Note: The effect of this attribute on jobs with multiple documents is
controlled by the "multiple-document-handling" job attribute (section
4.2.4) and the relationship of this attribute and the other
attributes that control document processing is described in section
15.3.
If the client supplies a value of 'none' along with any other
combination of values, it is the same as if only that other
combination of values had been supplied (that is the 'none' value has
no effect).
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4.2.7 page-ranges (1setOf rangeOfInteger (1:MAX))
This attribute identifies the range(s) of print-stream pages that the
Printer object uses for each copy of each document which are to be
printed. Nothing is printed for any pages identified that do not
exist in the document(s). Ranges MUST be in ascending order, for
example: 1-3, 5-7, 15-19 and MUST NOT overlap, so that a non-spooling
Printer object can process the job in a single pass. If the ranges
are not ascending or are overlapping, the IPP object MUST reject the
request and return the 'client-error-bad-request' status code. The
attribute is associated with print-stream pages not application-
numbered pages (for example, the page numbers found in the headers
and or footers for certain word processing applications).
For Jobs with multiple documents, the "multiple-document-handling"
attribute determines what constitutes a "copy" for purposes of the
specified page range(s). When "multiple-document-handling" is '
single-document', the Printer object MUST apply each supplied page
range once to the concatenation of the print-stream pages. For
example, if there are 8 documents of 10 pages each, the page-range '
41:60' prints the pages in the 5th and 6th documents as a single
document and none of the pages of the other documents are printed.
When "multiple-document-handling" is 'separate-documents-uncollated-
copies' or 'separate-documents-collated-copies', the Printer object
MUST apply each supplied page range repeatedly to each document copy.
For the same job, the page-range '1:3, 10:10' would print the first 3
pages and the 10th page of each of the 8 documents in the Job, as 8
separate documents.
In most cases, the exact pages to be printed will be generated by a
device driver and this attribute would not be required. However,
when printing an archived document which has already been formatted,
the end user may elect to print just a subset of the pages contained
in the document. In this case, if page-range = n.m is specified, the
first page to be printed will be page n. All subsequent pages of the
document will be printed through and including page m.
"page-ranges-supported" is a boolean value indicating whether or not
the printer is capable of supporting the printing of page ranges.
This capability may differ from one PDL to another. There is no
"page-ranges-default" attribute. If the "page-ranges" attribute is
not supplied by the client, all pages of the document will be
printed.
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Note: The effect of this attribute on jobs with multiple documents is
controlled by the "multiple-document-handling" job attribute (section
4.2.4) and the relationship of this attribute and the other
attributes that control document processing is described in section
15.3.
4.2.8 sides (type2 keyword)
This attribute specifies how print-stream pages are to be imposed
upon the sides of an instance of a selected medium, i.e., an
impression.
The standard keyword values are:
'one-sided': imposes each consecutive print-stream page upon the
same side of consecutive media sheets.
'two-sided-long-edge': imposes each consecutive pair of print-
stream pages upon front and back sides of consecutive media
sheets, such that the orientation of each pair of print-stream
pages on the medium would be correct for the reader as if for
binding on the long edge. This imposition is sometimes called '
duplex' or 'head-to-head'.
'two-sided-short-edge': imposes each consecutive pair of print-
stream pages upon front and back sides of consecutive media
sheets, such that the orientation of each pair of print-stream
pages on the medium would be correct for the reader as if for
binding on the short edge. This imposition is sometimes called
'tumble' or 'head-to-toe'.
'two-sided-long-edge', 'two-sided-short-edge', 'tumble', and 'duplex'
all work the same for portrait or landscape. However 'head-to-toe'
is 'tumble' in portrait but 'duplex' in landscape. 'head-to-head'
also switches between 'duplex' and 'tumble' when using portrait and
landscape modes.
Note: The effect of this attribute on jobs with multiple documents is
controlled by the "multiple-document-handling" job attribute (section
4.2.4) and the relationship of this attribute and the other
attributes that control document processing is described in section
15.3.
4.2.9 number-up (integer(1:MAX))
This attribute specifies the number of print-stream pages to impose
upon a single side of an instance of a selected medium. For example,
if the value is:
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Value Description
'1' the Printer MUST place one print-stream page on a single
side of an instance of the selected medium (MAY add
some sort of translation, scaling, or rotation).
'2' the Printer MUST place two print-stream pages on a single
side of an instance of the selected medium (MAY add
some sort of translation, scaling, or rotation).
'4' the Printer MUST place four print-stream pages on a single
side of an instance of the selected medium (MAY add
some sort of translation, scaling, or rotation).
This attribute primarily controls the translation, scaling and
rotation of print-stream pages.
Note: The effect of this attribute on jobs with multiple documents is
controlled by the "multiple-document-handling" job attribute (section
4.2.4) and the relationship of this attribute and the other
attributes that control document processing is described in section
15.3.
4.2.10 orientation-requested (type2 enum)
This attribute indicates the desired orientation for printed print-
stream pages; it does not describe the orientation of the client-
supplied print-stream pages.
For some document formats (such as 'application/postscript'), the
desired orientation of the print-stream pages is specified within the
document data. This information is generated by a device driver
prior to the submission of the print job. Other document formats
(such as 'text/plain') do not include the notion of desired
orientation within the document data. In the latter case it is
possible for the Printer object to bind the desired orientation to
the document data after it has been submitted. It is expected that a
Printer object would only support "orientations-requested" for some
document formats (e.g., 'text/plain' or 'text/html') but not others
(e.g., 'application/postscript'). This is no different than any
other Job Template attribute since section 4.2, item 1, points out
that a Printer object may support or not support any Job Template
attribute based on the document format supplied by the client.
However, a special mention is made here since it is very likely that
a Printer object will support "orientation-requested" for only a
subset of the supported document formats.
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Standard enum values are:
Value Symbolic Name and Description
'3' 'portrait': The content will be imaged across the short
edge of the medium.
'4' 'landscape': The content will be imaged across the long
edge of the medium. Landscape is defined to be a
rotation of the print-stream page to be imaged by +90
degrees with respect to the medium (i.e. anti-
clockwise) from the portrait orientation. Note: The
+90 direction was chosen because simple finishing on
the long edge is the same edge whether portrait or
landscape
'5' 'reverse-landscape': The content will be imaged across the
long edge of the medium. Reverse-landscape is defined
to be a rotation of the print-stream page to be imaged
by - 90 degrees with respect to the medium (i.e.
clockwise) from the portrait orientation. Note: The '
reverse-landscape' value was added because some
applications rotate landscape -90 degrees from
portrait, rather than +90 degrees.
'6' 'reverse-portrait': The content will be imaged across the
short edge of the medium. Reverse-portrait is defined
to be a rotation of the print-stream page to be imaged
by 180 degrees with respect to the medium from the
portrait orientation. Note: The 'reverse-portrait'
value was added for use with the "finishings"
attribute in cases where the opposite edge is desired
for finishing a portrait document on simple finishing
devices that have only one finishing position. Thus a
'text'/plain' portrait document can be stapled "on the
right" by a simple finishing device as is common use
with some middle eastern languages such as Hebrew.
Note: The effect of this attribute on jobs with multiple documents is
controlled by the "multiple-document-handling" job attribute (section
4.2.4) and the relationship of this attribute and the other
attributes that control document processing is described in section
15.3.
4.2.11 media (type3 keyword | name(MAX))
This attribute identifies the medium that the Printer uses for all
impressions of the Job.
The values for "media" include medium-names, medium-sizes, input-
trays and electronic forms so that one attribute specifies the media.
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If a Printer object supports a medium name as a value of this
attribute, such a medium name implicitly selects an input-tray that
contains the specified medium. If a Printer object supports a medium
size as a value of this attribute, such a medium size implicitly
selects a medium name that in turn implicitly selects an input-tray
that contains the medium with the specified size. If a Printer
object supports an input-tray as the value of this attribute, such an
input-tray implicitly selects the medium that is in that input-tray
at the time the job prints. This case includes manual-feed input-
trays. If a Printer object supports an electronic form as the value
of this attribute, such an electronic form implicitly selects a
medium-name that in turn implicitly selects an input-tray that
contains the medium specified by the electronic form. The electronic
form also implicitly selects an image that the Printer MUST merge
with the document data as its prints each page.
Standard keyword values are (taken from ISO DPA and the Printer MIB)
and are listed in section 14. An administrator MAY define additional
values using the 'name' or 'keyword' attribute syntax, depending on
implementation.
There is also an additional Printer attribute named "media-ready"
which differs from "media-supported" in that legal values only
include the subset of "media-supported" values that are physically
loaded and ready for printing with no operator intervention required.
If an IPP object supports "media-supported", it NEED NOT support
"media-ready".
The relationship of this attribute and the other attributes that
control document processing is described in section 15.3.
4.2.12 printer-resolution (resolution)
This attribute identifies the resolution that Printer uses for the
Job.
4.2.13 print-quality (type2 enum)
This attribute specifies the print quality that the Printer uses for
the Job.
The standard enum values are:
Value Symbolic Name and Description
'3' 'draft': lowest quality available on the printer
'4' 'normal': normal or intermediate quality on the printer
'5' 'high': highest quality available on the printer
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4.3 Job Description Attributes
The attributes in this section form the attribute group called "job-
description". The following table summarizes these attributes. The
third column indicates whether the attribute is a REQUIRED attribute
that MUST be supported by Printer objects. If it is not indicated as
REQUIRED, then it is OPTIONAL. The maximum size in octets for 'text'
and 'name' attributes is indicated in parenthesizes.
+----------------------------+----------------------+----------------+
| Attribute | Syntax | REQUIRED? |
+----------------------------+----------------------+----------------+
| job-uri | uri | REQUIRED |
+----------------------------+----------------------+----------------+
| job-id | integer(1:MAX) | REQUIRED |
+----------------------------+----------------------+----------------+
| job-printer-uri | uri | REQUIRED |
+----------------------------+----------------------+----------------+
| job-more-info | uri | |
+----------------------------+----------------------+----------------+
| job-name | name (MAX) | REQUIRED |
+----------------------------+----------------------+----------------+
| job-originating-user-name | name (MAX) | REQUIRED |
+----------------------------+----------------------+----------------+
| job-state | type1 enum | REQUIRED |
+----------------------------+----------------------+----------------+
| job-state-reasons | 1setOf type2 keyword | |
+----------------------------+----------------------+----------------+
| job-state-message | text (MAX) | |
+----------------------------+----------------------+----------------+
| number-of-documents | integer (0:MAX) | |
+----------------------------+----------------------+----------------+
| output-device-assigned | name (127) | |
+----------------------------+----------------------+----------------+
| time-at-creation | integer (0:MAX) | |
+----------------------------+----------------------+----------------+
| time-at-processing | integer (0:MAX) | |
+----------------------------+----------------------+----------------+
| time-at-completed | integer (0:MAX) | |
+----------------------------+----------------------+----------------+
| number-of-intervening-jobs | integer (0:MAX) | |
+----------------------------+----------------------+----------------+
| job-message-from-operator | text (127) | |
+----------------------------+----------------------+----------------+
| job-k-octets | integer (0:MAX) | |
+----------------------------+----------------------+----------------+
| job-impressions | integer (0:MAX) | |
+----------------------------+----------------------+----------------+
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+----------------------------+----------------------+----------------+
| Attribute | Syntax | REQUIRED? |
+----------------------------+----------------------+----------------+
| job-media-sheets | integer (0:MAX) | |
+----------------------------+----------------------+----------------+
| job-k-octets-processed | integer (0:MAX) | |
+----------------------------+----------------------+----------------+
| job-impressions-completed | integer (0:MAX) | |
+----------------------------+----------------------+----------------+
| job-media-sheets-completed | integer (0:MAX) | |
+----------------------------+----------------------+----------------+
| attributes-charset | charset | REQUIRED |
+----------------------------+----------------------+----------------+
| attributes-natural-language| naturalLanguage | REQUIRED |
+----------------------------+----------------------+----------------+
4.3.1 job-uri (uri)
This REQUIRED attribute contains the URI for the job. The Printer
object, on receipt of a new job, generates a URI which identifies the
new Job. The Printer object returns the value of the "job-uri"
attribute as part of the response to a create request. The precise
format of a Job URI is implementation dependent. If the Printer
object supports more than one URI and there is some relationship
between the newly formed Job URI and the Printer object's URI, the
Printer object uses the Printer URI supplied by the client in the
create request. For example, if the create request comes in over a
secure channel, the new Job URI MUST use the same secure channel.
This can be guaranteed because the Printer object is responsible for
generating the Job URI and the Printer object is aware of its
security configuration and policy as well as the Printer URI used in
the create request.
For a description of this attribute and its relationship to "job-id"
and "job-printer-uri" attribute, see the discussion in section 2.4 on
"Object Identity".
4.3.2 job-id (integer(1:MAX))
This REQUIRED attribute contains the ID of the job. The Printer, on
receipt of a new job, generates an ID which identifies the new Job on
that Printer. The Printer returns the value of the "job-id"
attribute as part of the response to a create request. The 0 value
is not included to allow for compatibility with SNMP index values
which also cannot be 0.
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For a description of this attribute and its relationship to "job-uri"
and "job-printer-uri" attribute, see the discussion in section 2.4 on
"Object Identity".
4.3.3 job-printer-uri (uri)
This REQUIRED attribute identifies the Printer object that created
this Job object. When a Printer object creates a Job object, it
populates this attribute with the Printer object URI that was used in
the create request. This attribute permits a client to identify the
Printer object that created this Job object when only the Job
object's URI is available to the client. The client queries the
creating Printer object to determine which languages, charsets,
operations, are supported for this Job.
For a description of this attribute and its relationship to "job-uri"
and "job-id" attribute, see the discussion in section 2.4 on "Object
Identity".
4.3.4 job-more-info (uri)
Similar to "printer-more-info", this attribute contains the URI
referencing some resource with more information about this Job
object, perhaps an HTML page containing information about the Job.
4.3.5 job-name (name(MAX))
This REQUIRED attribute is the name of the job. It is a name that is
more user friendly than the "job-uri" attribute value. It does not
need to be unique between Jobs. The Job's "job-name" attribute is
set to the value supplied by the client in the "job-name" operation
attribute in the create request (see Section 3.2.1.1). If, however,
the "job-name" operation attribute is not supplied by the client in
the create request, the Printer object, on creation of the Job, MUST
generate a name. The printer SHOULD generate the value of the Job's
"job-name" attribute from the first of the following sources that
produces a value: 1) the "document-name" operation attribute of the
first (or only) document, 2) the "document-URI" attribute of the
first (or only) document, or 3) any other piece of Job specific
and/or Document Content information.
4.3.6 job-originating-user-name (name(MAX))
This REQUIRED attribute contains the name of the end user that
submitted the print job. The Printer object sets this attribute to
the most authenticated printable name that it can obtain from the
authentication service over which the IPP operation was received.
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Only if such is not available, does the Printer object use the value
supplied by the client in the "requesting-user-name" operation
attribute of the create operation (see Section 8).
Note: The Printer object needs to keep an internal originating user
id of some form, typically as a credential of a principal, with the
Job object. Since such an internal attribute is implementation-
dependent and not of interest to clients, it is not specified as a
Job Description attribute. This originating user id is used for
authorization checks (if any) on all subsequent operation.
4.3.7 job-state (type1 enum)
This REQUIRED attribute identifies the current state of the job.
Even though the IPP protocol defines eight values for job states,
implementations only need to support those states which are
appropriate for the particular implementation. In other words, a
Printer supports only those job states implemented by the output
device and available to the Printer object implementation.
Standard enum values are:
Values Symbolic Name and Description
'3' 'pending': The job is a candidate to start processing, but
is not yet processing.
'4' 'pending-held': The job is not a candidate for processing
for any number of reasons but will return to the '
pending' state as soon as the reasons are no longer
present. The job's "job-state-reason" attribute MUST
indicate why the job is no longer a candidate for
processing.
'5' 'processing': One or more of:
1. the job is using, or is attempting to use, one or
more purely software processes that are analyzing,
creating, or interpreting a PDL, etc.,
2. the job is using, or is attempting to use, one or
more hardware devices that are interpreting a PDL,
making marks on a medium, and/or performing finishing,
such as stapling, etc.,
3. the Printer object has made the job ready for
printing, but the output device is not yet printing
it, either because the job hasn't reached the output
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device or because the job is queued in the output
device or some other spooler, awaiting the output
device to print it.
When the job is in the 'processing' state, the entire
job state includes the detailed status represented in
the printer's "printer-state", "printer-state-
reasons", and "printer-state-message" attributes.
Implementations MAY, though they NEED NOT, include
additional values in the job's "job-state-reasons"
attribute to indicate the progress of the job, such as
adding the 'job-printing' value to indicate when the
output device is actually making marks on paper and/or
the 'processing-to-stop-point' value to indicate that
the IPP object is in the process of canceling or
aborting the job. Most implementations won't bother
with this nuance.
'6' 'processing-stopped': The job has stopped while processing
for any number of reasons and will return to the '
processing' state as soon as the reasons are no longer
present.
The job's "job-state-reason" attribute MAY indicate
why the job has stopped processing. For example, if
the output device is stopped, the 'printer-stopped'
value MAY be included in the job's "job-state-reasons"
attribute.
Note: When an output device is stopped, the device
usually indicates its condition in human readable form
locally at the device. A client can obtain more
complete device status remotely by querying the
Printer object's "printer-state", "printer-state-
reasons" and "printer-state-message" attributes.
'7' 'canceled': The job has been canceled by a Cancel-Job
operation and the Printer object has completed
canceling the job and all job status attributes have
reached their final values for the job. While the
Printer object is canceling the job, the job remains
in its current state, but the job's "job-state-
reasons" attribute SHOULD contain the 'processing-to-
stop-point' value and one of the 'canceled-by-user', '
canceled-by-operator', or 'canceled-at-device' value.
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When the job moves to the 'canceled' state, the '
processing-to-stop-point' value, if present, MUST be
removed, but the 'canceled-by-xxx', if present, MUST
remain.
'8' 'aborted': The job has been aborted by the system, usually
while the job was in the 'processing' or 'processing-
stopped' state and the Printer has completed aborting
the job and all job status attributes have reached
their final values for the job. While the Printer
object is aborting the job, the job remains in its
current state, but the job's "job-state-reasons"
attribute SHOULD contain the 'processing-to-stop-
point' and 'aborted-by-system' values. When the job
moves to the 'aborted' state, the 'processing-to-
stop-point' value, if present, MUST be removed, but
the 'aborted-by-system' value, if present, MUST
remain.
'9' 'completed': The job has completed successfully or with
warnings or errors after processing and all of the job
media sheets have been successfully stacked in the
appropriate output bin(s) and all job status
attributes have reached their final values for the
job. The job's "job-state-reasons" attribute SHOULD
contain one of: 'completed-successfully', '
completed-with-warnings', or 'completed-with-errors'
values.
The final value for this attribute MUST be one of: 'completed', '
canceled', or 'aborted' before the Printer removes the job
altogether. The length of time that jobs remain in the 'canceled', '
aborted', and 'completed' states depends on implementation.
The following figure shows the normal job state transitions.
+----> canceled
/
+----> pending --------> processing ---------+------> completed
| ^ ^ \
--->+ | | +----> aborted
| v v /
+----> pending-held processing-stopped ---+
Normally a job progresses from left to right. Other state
transitions are unlikely, but are not forbidden. Not shown are the
transitions to the 'canceled' state from the 'pending', 'pending-
held', and 'processing-stopped' states.
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Jobs reach one of the three terminal states: 'completed', 'canceled',
or 'aborted', after the jobs have completed all activity, including
stacking output media, after the jobs have completed all activity,
and all job status attributes have reached their final values for the
job.
Note: As with all other IPP attributes, if the implementation can not
determine the correct value for this attribute, it SHOULD respond
with the out-of-band value 'unknown' (see section 4.1) rather than
try to guess at some possibly incorrect value and give the end user
the wrong impression about the state of the Job object. For example,
if the implementation is just a gateway into some printing system
that does not provide detailed status about the print job, the IPP
Job object's state might literally be 'unknown'.
4.3.8 job-state-reasons (1setOf type2 keyword)
This attribute provides additional information about the job's
current state, i.e., information that augments the value of the job's
"job-state" attribute.
Implementation of these values is OPTIONAL, i.e., a Printer NEED NOT
implement them, even if (1) the output device supports the
functionality represented by the reason and (2) is available to the
Printer object implementation. These values MAY be used with any job
state or states for which the reason makes sense. Furthermore, when
implemented, the Printer MUST return these values when the reason
applies and MUST NOT return them when the reason no longer applies
whether the value of the Job's "job-state" attribute changed or not.
When the Job does not have any reasons for being in its current
state, the value of the Job's "job-state-reasons" attribute MUST be '
none'.
Note: While values cannot be added to the 'job-state' attribute
without impacting deployed clients that take actions upon receiving
"job-state" values, it is the intent that additional "job-state-
reasons" values can be defined and registered without impacting such
deployed clients. In other words, the "job-state-reasons" attribute
is intended to be extensible.
The following standard keyword values are defined. For ease of
understanding, the values are presented in the order in which the
reasons are likely to occur (if implemented), starting with the '
job-incoming' value:
'none': There are no reasons for the job's current state.
'job-incoming': The Create-Job operation has been accepted by the
Printer, but the Printer is expecting additional Send-Document
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and/or Send-URI operations and/or is accessing/accepting
document data.
'submission-interrupted': The job was not completely submitted for
some unforeseen reason, such as: (1) the Printer has crashed
before the job was closed by the client, (2) the Printer or the
document transfer method has crashed in some non-recoverable way
before the document data was entirely transferred to the
Printer, (3) the client crashed or failed to close the job
before the time-out period. See section 4.4.28.
'job-outgoing': The Printer is transmitting the job to the output
device.
'job-hold-until-specified': The value of the job's "job-hold-
until" attribute was specified with a time period that is still
in the future. The job MUST NOT be a candidate for processing
until this reason is removed and there are no other reasons to
hold the job.
'resources-are-not-ready': At least one of the resources needed by
the job, such as media, fonts, resource objects, etc., is not
ready on any of the physical printer's for which the job is a
candidate. This condition MAY be detected when the job is
accepted, or subsequently while the job is pending or
processing, depending on implementation. The job may remain in
its current state or be moved to the 'pending-held' state,
depending on implementation and/or job scheduling policy.
'printer-stopped-partly': The value of the Printer's "printer-
state-reasons" attribute contains the value 'stopped-partly'.
'printer-stopped': The value of the Printer's "printer-state"
attribute is 'stopped'.
'job-interpreting': Job is in the 'processing' state, but more
specifically, the Printer is interpreting the document data.
'job-queued': Job is in the 'processing' state, but more
specifically, the Printer has queued the document data.
'job-transforming': Job is in the 'processing' state, but more
specifically, the Printer is interpreting document data and
producing another electronic representation.
'job-printing': The output device is marking media. This value is
useful for Printers which spend a great deal of time processing
(1) when no marking is happening and then want to show that
marking is now happening or (2) when the job is in the process
of being canceled or aborted while the job remains in the '
processing' state, but the marking has not yet stopped so that
impression or sheet counts are still increasing for the job.
'job-canceled-by-user': The job was canceled by the owner of the
job using the Cancel-Job request, i.e., by a user whose
authenticated identity is the same as the value of the
originating user that created the Job object, or by some other
authorized end-user, such as a member of the job owner's
security group.
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'job-canceled-by-operator': The job was canceled by the operator
using the Cancel-Job request, i.e., by a user who has been
authenticated as having operator privileges (whether local or
remote). If the security policy is to allow anyone to cancel
anyone's job, then this value may be used when the job is
canceled by other than the owner of the job. For such a
security policy, in effect, everyone is an operator as far as
canceling jobs with IPP is concerned.
'job-canceled-at-device': The job was canceled by an unidentified
local user, i.e., a user at a console at the device.
'aborted-by-system': The job (1) is in the process of being
aborted, (2) has been aborted by the system and placed in the '
aborted' state, or (3) has been aborted by the system and placed
in the 'pending-held' state, so that a user or operator can
manually try the job again.
'processing-to-stop-point': The requester has issued a Cancel-Job
operation or the Printer object has aborted the job, but is
still performing some actions on the job until a specified stop
point occurs or job termination/cleanup is completed.
This reason is recommended to be used in conjunction with the '
processing' job state to indicate that the Printer object is
still performing some actions on the job while the job remains
in the 'processing' state. After all the job's job description
attributes have stopped incrementing, the Printer object moves
the job from the 'processing' state to the 'canceled' or '
aborted' job states.
'service-off-line': The Printer is off-line and accepting no jobs.
All 'pending' jobs are put into the 'pending-held' state. This
situation could be true if the service's or document transform's
input is impaired or broken.
'job-completed-successfully': The job completed successfully.
'job-completed-with-warnings': The job completed with warnings.
'job-completed-with-errors': The job completed with errors (and
possibly warnings too).
4.3.9 job-state-message (text(MAX))
This attribute specifies information about the "job-state" and "job-
state-reasons" attributes in human readable text. If the Printer
object supports this attribute, the Printer object MUST be able to
generate this message in any of the natural languages identified by
the Printer's "generated-natural-language-supported" attribute (see
the "attributes-natural-language" operation attribute specified in
Section 3.1.4.1).
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Note: the value SHOULD NOT contain additional information not
contained in the values of the "job-state" and "job-states-reasons"
attributes, such as interpreter error information. Otherwise,
application programs might attempt to parse the (localized text).
For such additional information such as interpreter errors for
application program consumption, a new attribute with keyword values,
needs to be developed and registered.
4.3.10 number-of-documents (integer(0:MAX))
This attribute indicates the number of documents in the job, i.e.,
the number of Send-Document, Send-URI, Print-Job, or Print-URI
operations that the Printer has accepted for this job, regardless of
whether the document data has reached the Printer object or not.
Implementations supporting the OPTIONAL Create-Job/Send-
Document/Send-URI operations SHOULD support this attribute so that
clients can query the number of documents in each job.
4.3.11 output-device-assigned (name(127))
This attribute identifies the output device to which the Printer
object has assigned this job. If an output device implements an
embedded Printer object, the Printer object NEED NOT set this
attribute. If a print server implements a Printer object, the value
MAY be empty (zero-length string) or not returned until the Printer
object assigns an output device to the job. This attribute is
particularly useful when a single Printer object support multiple
devices (so called "fan-out").
4.3.12 time-at-creation (integer(0:MAX))
This attribute indicates the point in time at which the Job object
was created. In order to populate this attribute, the Printer object
uses the value in its "printer-up-time" attribute at the time the Job
object is created.
4.3.13 time-at-processing (integer(0:MAX))
This attribute indicates the point in time at which the Job object
began processing. In order to populate this attribute, the Printer
object uses the value in its "printer-up-time" attribute at the time
the Job object is moved into the 'processing' state for the first
time.
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4.3.14 time-at-completed (integer(0:MAX))
This attribute indicates the point in time at which the Job object
completed (or was cancelled or aborted). In order to populate this
attribute, the Printer object uses the value in its "printer-up-time"
attribute at the time the Job object is moved into the 'completed' or
'canceled' or 'aborted' state.
4.3.15 number-of-intervening-jobs (integer(0:MAX))
This attribute indicates the number of jobs that are "ahead" of this
job in the relative chronological order of expected time to complete
(i.e., the current scheduled order). For efficiency, it is only
necessary to calculate this value when an operation is performed that
requests this attribute.
4.3.16 job-message-from-operator (text(127))
This attribute provides a message from an operator, system
administrator or "intelligent" process to indicate to the end user
the reasons for modification or other management action taken on a
job.
4.3.17 job-k-octets (integer(0:MAX))
This attribute specifies the total size of the document(s) in K
octets, i.e., in units of 1024 octets requested to be processed in
the job. The value MUST be rounded up, so that a job between 1 and
1024 octets MUST be indicated as being 1, 1025 to 2048 MUST be 2,
etc.
This value MUST NOT include the multiplicative factors contributed by
the number of copies specified by the "copies" attribute, independent
of whether the device can process multiple copies without making
multiple passes over the job or document data and independent of
whether the output is collated or not. Thus the value is independent
of the implementation and indicates the size of the document(s)
measured in K octets independent of the number of copies.
This value MUST also not include the multiplicative factor due to a
copies instruction embedded in the document data. If the document
data actually includes replications of the document data, this value
will include such replication. In other words, this value is always
the size of the source document data, rather than a measure of the
hardcopy output to be produced.
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Note: This attribute and the following two attributes ("job-
impressions" and "job-media-sheets") are not intended to be counters;
they are intended to be useful routing and scheduling information if
known. For these three attributes, the Printer object may try to
compute the value if it is not supplied in the create request. Even
if the client does supply a value for these three attributes in the
create request, the Printer object MAY choose to change the value if
the Printer object is able to compute a value which is more accurate
than the client supplied value. The Printer object may be able to
determine the correct value for these three attributes either right
at job submission time or at any later point in time.
4.3.18 job-impressions (integer(0:MAX))
This attribute specifies the total size in number of impressions of
the document(s) being submitted (see the definition of impression in
section 13.2.5).
As with "job-k-octets", this value MUST NOT include the
multiplicative factors contributed by the number of copies specified
by the "copies" attribute, independent of whether the device can
process multiple copies without making multiple passes over the job
or document data and independent of whether the output is collated or
not. Thus the value is independent of the implementation and
reflects the size of the document(s) measured in impressions
independent of the number of copies.
As with "job-k-octets", this value MUST also not include the
multiplicative factor due to a copies instruction embedded in the
document data. If the document data actually includes replications
of the document data, this value will include such replication. In
other words, this value is always the number of impressions in the
source document data, rather than a measure of the number of
impressions to be produced by the job.
See the Note in the "job-k-octets" attribute that also applies to
this attribute.
4.3.19 job-media-sheets (integer(0:MAX))
This attribute specifies the total number of media sheets to be
produced for this job.
Unlike the "job-k-octets" and the "job-impressions" attributes, this
value MUST include the multiplicative factors contributed by the
number of copies specified by the "copies" attribute and a 'number of
copies' instruction embedded in the document data, if any. This
difference allows the system administrator to control the lower and
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upper bounds of both (1) the size of the document(s) with "job-k-
octets-supported" and "job-impressions-supported" and (2) the size of
the job with "job-media-sheets-supported".
See the Note in the "job-k-octets" attribute that also applies to
this attribute.
4.3.20 job-k-octets-processed (integer(0:MAX))
This attribute specifies the total number of octets processed in K
octets, i.e., in units of 1024 octets so far. The value MUST be
rounded up, so that a job between 1 and 1024 octets inclusive MUST be
indicated as being 1, 1025 to 2048 inclusive MUST be 2, etc.
For implementations where multiple copies are produced by the
interpreter with only a single pass over the data, the final value
MUST be equal to the value of the "job-k-octets" attribute. For
implementations where multiple copies are produced by the interpreter
by processing the data for each copy, the final value MUST be a
multiple of the value of the "job-k-octets" attribute.
Note: This attribute and the following two attributes ("job-
impressions-completed" and "job-sheets-completed") are intended to be
counters. That is, the value for a job that has not started
processing MUST be 0. When the job's "job-state" is 'processing' or
'processing-stopped', this value is intended to contain the amount of
the job that has been processed to the time at which the attributes
are requested.
4.3.21 job-impressions-completed (integer(0:MAX))
This job attribute specifies the number of impressions completed for
the job so far. For printing devices, the impressions completed
includes interpreting, marking, and stacking the output.
See the note in "job-k-octets-processed" which also applies to this
attribute.
4.3.22 job-media-sheets-completed (integer(0:MAX))
This job attribute specifies the media-sheets completed marking and
stacking for the entire job so far whether those sheets have been
processed on one side or on both.
See the note in "job-k-octets-processed" which also applies to this
attribute.
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4.3.23 attributes-charset (charset)
This REQUIRED attribute is populated using the value in the client
supplied "attributes-charset" attribute in the create request. It
identifies the charset (coded character set and encoding method) used
by any Job attributes with attribute syntax 'text' and 'name' that
were supplied by the client in the create request. See Section 3.1.4
for a complete description of the "attributes-charset" operation
attribute.
This attribute does not indicate the charset in which the 'text' and
'name' values are stored internally in the Job object. The internal
charset is implementation-defined. The IPP object MUST convert from
whatever the internal charset is to that being requested in an
operation as specified in Section 3.1.4.
4.3.24 attributes-natural-language (naturalLanguage)
This REQUIRED attribute is populated using the value in the client
supplied "attributes-natural-language" attribute in the create
request. It identifies the natural language used for any Job
attributes with attribute syntax 'text' and 'name' that were supplied
by the client in the create request. See Section 3.1.4 for a
complete description of the "attributes-natural-language" operation
attribute. See Sections 4.1.1.2 and 4.1.2.2 for how a Natural
Language Override may be supplied explicitly for each 'text' and '
name' attribute value that differs from the value identified by the
"attributes-natural-language" attribute.
4.4 Printer Description Attributes
These attributes form the attribute group called "printer-
description". The following table summarizes these attributes, their
syntax, and whether or not they are REQUIRED for a Printer object to
support. If they are not indicated as REQUIRED, they are OPTIONAL.
The maximum size in octets for 'text' and 'name' attributes is
indicated in parenthesizes.
Note: How these attributes are set by an Administrator is outside the
scope of this specification.
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+----------------------------+----------------------+----------------+
| Attribute | Syntax | REQUIRED? |
+----------------------------+----------------------+----------------+
| printer-uri-supported | 1setOf uri | REQUIRED |
+----------------------------+----------------------+----------------+
| uri-security-supported | 1setOf type2 keyword | REQUIRED |
+----------------------------+----------------------+----------------+
| printer-name | name (127) | REQUIRED |
+----------------------------+----------------------+----------------+
| printer-location | text (127) | |
+----------------------------+----------------------+----------------+
| printer-info | text (127) | |
+----------------------------+----------------------+----------------+
| printer-more-info | uri | |
+----------------------------+----------------------+----------------+
| printer-driver-installer | uri | |
+----------------------------+----------------------+----------------+
| printer-make-and-model | text (127) | |
+----------------------------+----------------------+----------------+
| printer-more-info- | uri | |
| manufacturer | | |
+----------------------------+----------------------+----------------+
| printer-state | type1 enum | REQUIRED |
+----------------------------+----------------------+----------------+
| printer-state-reasons | 1setOf type2 keyword | |
+----------------------------+----------------------+----------------+
| printer-state-message | text (MAX) | |
+----------------------------+----------------------+----------------+
| operations-supported | 1setOf type2 enum | REQUIRED |
+----------------------------+----------------------+----------------+
| charset-configured | charset | REQUIRED |
+----------------------------+----------------------+----------------+
| charset-supported | 1setOf charset | REQUIRED |
+----------------------------+----------------------+----------------+
| natural-language-configured| naturalLanguage | REQUIRED |
+----------------------------+----------------------+----------------+
| generated-natural-language-| 1setOf | REQUIRED |
| supported | naturalLanguage | |
+----------------------------+----------------------+----------------+
| document-format-default | mimeMediaType | REQUIRED |
+----------------------------+----------------------+----------------+
| document-format- | 1setOf | REQUIRED |
| supported | mimeMediaType | |
+----------------------------+----------------------+----------------+
| printer-is-accepting-jobs | boolean | REQUIRED |
+----------------------------+----------------------+----------------+
| queued-job-count | integer (0:MAX) | RECOMMENDED |
+----------------------------+----------------------+----------------+
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+----------------------------+----------------------+----------------+
| Attribute | Syntax | REQUIRED? |
+----------------------------+----------------------+----------------+
| printer-message-from- | text (127) | |
| operator | | |
+----------------------------+----------------------+----------------+
| color-supported | boolean | |
+----------------------------+----------------------+----------------+
| reference-uri-schemes- | 1setOf uriScheme | |
| supported | | |
+----------------------------+----------------------+----------------+
| pdl-override-supported | type2 keyword | REQUIRED |
+----------------------------+----------------------+----------------+
| printer-up-time | integer (1:MAX) | REQUIRED |
+----------------------------+----------------------+----------------+
| printer-current-time | dateTime | |
+----------------------------+----------------------+----------------+
| multiple-operation-time-out| integer (1:MAX) | |
+----------------------------+----------------------+----------------+
| compression-supported | 1setOf type3 keyword | |
+----------------------------+----------------------+----------------+
| job-k-octets-supported | rangeOfInteger | |
| | (0:MAX) | |
+----------------------------+----------------------+----------------+
| job-impressions-supported | rangeOfInteger | |
| | (0:MAX) | |
+----------------------------+----------------------+----------------+
| job-media-sheets-supported | rangeOfInteger | |
| | (0:MAX) | |
+----------------------------+----------------------+----------------+
4.4.1 printer-uri-supported (1setOf uri)
This REQUIRED Printer attribute contains at least one URI for the
Printer object. It OPTIONALLY contains more than one URI for the
Printer object. An administrator determines a Printer object's
URI(s) and configures this attribute to contain those URIs by some
means outside the scope of IPP/1.0. The precise format of this URI
is implementation dependent and depends on the protocol. See the
next section for a description "uri-security-supported" which is the
REQUIRED companion attribute to this "printer-uri-supported"
attribute. See section 2.4 on Printer object identity and section
8.2 on security and URIs for more information.
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4.4.2 uri-security-supported (1setOf type2 keyword)
This REQUIRED Printer attribute MUST have the same cardinality
(contain the same number of values) as the "printer-uri-supported"
attribute. This attribute identifies the security mechanisms used
for each URI listed in the "printer-uri-supported" attribute. The "i
th" value in "uri-security-supported" corresponds to the "i th" value
in "printer-uri-supported" and it describes the security mechanisms
used for accessing the Printer object via that URI. The following
standard values are defined:
'none': There are no secure communication channel protocols in use
for the given URI.
'ssl3': SSL3 [SSL] is the secure communications channel protocol in
use for the given URI.
Consider the following example. For a single Printer object, an
administrator configures the "printer-uri-supported" and "uri-
security-supported" attributes as follows:
"printer-uri-supported": 'http://acme.com/open-use-printer', '
http://acme.com/restricted-use-printer', '
http://acme.com/private-printer'
"uri-security-supported": 'none', 'none', 'ssl3'
In this case, one Printer object has three URIs.
- For the first URI, 'http://acme.com/open-use-printer', the value
'none' in "uri-security-supported" indicates that there is no
secure channel protocol configured to run under HTTP. The name
implies that there is no Basic or Digest authentication being
used, but it is up to the client to determine that while using
HTTP underneath the IPP application protocol.
- For the second URI, 'http://acme.com/restricted-use-printer', the
value 'none' in "uri-security-supported" indicates that there is
no secure channel protocol configured to run under HTTP. In
this case, although the name does imply that there is some sort
of Basic or Digest authentication being used within HTTP, it is
up to the client to determine that while using HTTP and by
processing any '401 Unauthorized' HTTP error messages.
- For the third URI, 'http://acme.com/private-printer', the value '
ssl3' in "uri-security-supported" indicates that SSL3 is being
used to secure the channel. The client SHOULD be prepared to
use SSL3 framing to negotiate an acceptable ciphersuite to use
while communicating with the Printer object. In this case, the
name implies the use of a secure communications channel, but the
fact is made explicit by the presence of the 'ssl3' value in
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"uri-security-supported". The client does not need to resort to
understanding which security it must use by following naming
conventions or by parsing the URI to determine which security
mechanisms are implied.
It is expected that many IPP Printer objects will be configured to
support only one channel (either configured to use SSL3 access or
not), and will therefore only ever have one URI listed in the
"printer-uri-supported" attribute. No matter the configuration of
the Printer object (whether it has only one URI or more than one
URI), a client MUST supply only one URI in the target "printer-uri"
operation attribute.
4.4.3 printer-name (name(127))
This REQUIRED Printer attribute contains the name of the Printer
object. It is a name that is more end-user friendly than a URI. An
administrator determines a printer's name and sets this attribute to
that name. This name may be the last part of the printer's URI or it
may be unrelated. In non-US-English locales, a name may contain
characters that are not allowed in a URI.
4.4.4 printer-location (text(127))
This Printer attribute identifies the location of the device. This
could include things like: "in Room 123A, second floor of building
XYZ".
4.4.5 printer-info (text(127))
This Printer attribute identifies the descriptive information about
this Printer object. This could include things like: "This printer
can be used for printing color transparencies for HR presentations",
or "Out of courtesy for others, please print only small (1-5 page)
jobs at this printer", or even "This printer is going away on July 1,
1997, please find a new printer".
4.4.6 printer-more-info (uri)
This Printer attribute contains a URI used to obtain more information
about this specific Printer object. For example, this could be an
HTTP type URI referencing an HTML page accessible to a Web Browser.
The information obtained from this URI is intended for end user
consumption. Features outside the scope of IPP can be accessed from
this URI. The information is intended to be specific to this printer
instance and site specific services (e.g. job pricing, services
offered, end user assistance). The device manufacturer may initially
populate this attribute.
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4.4.7 printer-driver-installer (uri)
This Printer attribute contains a URI to use to locate the driver
installer for this Printer object. This attribute is intended for
consumption by automata. The mechanics of print driver installation
is outside the scope of IPP. The device manufacturer may initially
populate this attribute.
4.4.8 printer-make-and-model (text(127))
This Printer attribute identifies the make and model of the device.
The device manufacturer may initially populate this attribute.
4.4.9 printer-more-info-manufacturer (uri)
This Printer attribute contains a URI used to obtain more information
about this type of device. The information obtained from this URI is
intended for end user consumption. Features outside the scope of IPP
can be accessed from this URI (e.g., latest firmware, upgrades, print
drivers, optional features available, details on color support). The
information is intended to be germane to this printer without regard
to site specific modifications or services. The device manufacturer
may initially populate this attribute.
4.4.10 printer-state (type1 enum)
This REQUIRED Printer attribute identifies the current state of the
device. The "printer-state reasons" attribute augments the
"printer-state" attribute to give more detailed information about the
Printer in the given printer state.
A Printer object need only update this attribute before responding to
an operation which requests the attribute; the Printer object NEED
NOT update this attribute continually, since asynchronous event
notification is not part of IPP/1.0. A Printer NEED NOT implement
all values if they are not applicable to a given implementation.
The following standard enum values are defined:
Value Symbolic Name and Description
'3' 'idle': If a Printer receives a job (whose required
resources are ready) while in this state, such a job
MUST transit into the 'processing' state immediately.
If the "printer-state-reasons" attribute contains any
reasons, they MUST be reasons that would not prevent a
job from transiting into the 'processing' state
immediately, e.g., 'toner-low'. Note: if a Printer
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controls more than one output device, the above
definition implies that a Printer is 'idle' if at
least one output device is idle.
'4' 'processing': If a Printer receives a job (whose required
resources are ready) while in this state, such a job
MUST transit into the 'pending' state immediately.
Such a job MUST transit into the 'processing' state
only after jobs ahead of it complete. If the
"printer-state-reasons" attribute contains any
reasons, they MUST be reasons that do not prevent the
current job from printing, e.g. 'toner-low'. Note:
if a Printer controls more than one output device, the
above definition implies that a Printer is '
processing' if at least one output device is
processing, and none is idle.
'5' 'stopped': If a Printer receives a job (whose required
resources are ready) while in this state, such a job
MUST transit into the 'pending' state immediately.
Such a job MUST transit into the 'processing' state
only after some human fixes the problem that stopped
the printer and after jobs ahead of it complete
processing. If supported, the "printer-state-reasons"
attribute MUST contain at least one reason, e.g. '
media-jam', which prevents it from either processing
the current job or transitioning a 'pending' job to
the 'processing' state.
Note: if a Printer controls more than one output
device, the above definition implies that a Printer is
'stopped' only if all output devices are stopped.
Also, it is tempting to define 'stopped' as when a
sufficient number of output devices are stopped and
leave it to an implementation to define the sufficient
number. But such a rule complicates the definition of
'stopped' and 'processing'. For example, with this
alternate definition of 'stopped', a job can move from
'pending' to 'processing' without human intervention,
even though the Printer is stopped.
4.4.11 printer-state-reasons (1setOf type2 keyword)
This Printer attribute supplies additional detail about the device's
state.
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Each keyword value MAY have a suffix to indicate its level of
severity. The three levels are: report (least severe), warning, and
error (most severe).
- '-report': This suffix indicates that the reason is a "report".
An implementation may choose to omit some or all reports. Some
reports specify finer granularity about the printer state;
others serve as a precursor to a warning. A report MUST contain
nothing that could affect the printed output.
- '-warning': This suffix indicates that the reason is a "warning".
An implementation may choose to omit some or all warnings.
Warnings serve as a precursor to an error. A warning MUST
contain nothing that prevents a job from completing, though in
some cases the output may be of lower quality.
- '-error': This suffix indicates that the reason is an "error".
An implementation MUST include all errors. If this attribute
contains one or more errors, printer MUST be in the stopped
state.
If the implementation does not add any one of the three suffixes, all
parties MUST assume that the reason is an "error".
If a Printer object controls more than one output device, each value
of this attribute MAY apply to one or more of the output devices. An
error on one output device that does not stop the Printer object as a
whole MAY appear as a warning in the Printer's "printer-state-reasons
attribute". If the "printer-state" for such a Printer has a value of
'stopped', then there MUST be an error reason among the values in the
"printer-state-reasons" attribute.
The following standard keyword values are defined:
'other': The device has detected an error other than one listed in
this document.
'none': There are not reasons. This state reason is semantically
equivalent to "printer-state-reasons" without any value.
'media-needed': A tray has run out of media.
'media-jam': The device has a media jam.
'paused': Someone has paused the Printer object. In this state, a
Printer MUST NOT produce printed output, but it MUST perform
other operations requested by a client. If a Printer had been
printing a job when the Printer was paused, the Printer MUST
resume printing that job when the Printer is no longer paused
and leave no evidence in the printed output of such a pause.
'shutdown': Someone has removed a Printer object from service, and
the device may be powered down or physically removed. In this
state, a Printer object MUST NOT produce printed output, and
unless the Printer object is realized by a print server that is
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still active, the Printer object MUST perform no other
operations requested by a client, including returning this
value. If a Printer object had been printing a job when it was
shutdown, the Printer NEED NOT resume printing that job when the
Printer is no longer shutdown. If the Printer resumes printing
such a job, it may leave evidence in the printed output of such
a shutdown, e.g. the part printed before the shutdown may be
printed a second time after the shutdown.
'connecting-to-device': The Printer object has scheduled a job on
the output device and is in the process of connecting to a
shared network output device (and might not be able to actually
start printing the job for an arbitrarily long time depending on
the usage of the output device by other servers on the network).
'timed-out': The server was able to connect to the output device
(or is always connected), but was unable to get a response from
the output device.
'stopping': The Printer object is in the process of stopping the
device and will be stopped in a while. When the device is
stopped, the Printer object will change the Printer object's
state to 'stopped'. The 'stopping-warning' reason is never an
error, even for a Printer with a single output device. When an
output-device ceases accepting jobs, the Printer will have this
reason while the output device completes printing.
'stopped-partly': When a Printer object controls more than one
output device, this reason indicates that one or more output
devices are stopped. If the reason is a report, fewer than half
of the output devices are stopped. If the reason is a warning,
fewer than all of the output devices are stopped.
'toner-low': The device is low on toner.
'toner-empty': The device is out of toner.
'spool-area-full': The limit of persistent storage allocated for
spooling has been reached.
'cover-open': One or more covers on the device are open.
'interlock-open': One or more interlock devices on the printer are
unlocked.
'door-open': One or more doors on the device are open.
'input-tray-missing': One or more input trays are not in the
device.
'media-low': At least one input tray is low on media.
'media-empty': At least one input tray is empty.
'output-tray-missing': One or more output trays are not in the
device
'output-area-almost-full': One or more output area is almost full
(e.g. tray, stacker, collator).
'output-area-full': One or more output area is full. (e.g. tray,
stacker, collator)
'marker-supply-low': The device is low on at least one marker
supply. (e.g. toner, ink, ribbon)
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'marker-supply-empty: The device is out of at least one marker
supply. (e.g. toner, ink, ribbon)
'marker-waste-almost-full': The device marker supply waste
receptacle is almost full.
'marker-waste-full': The device marker supply waste receptacle is
full.
'fuser-over-temp': The fuser temperature is above normal.
'fuser-under-temp': The fuser temperature is below normal.
'opc-near-eol': The optical photo conductor is near end of life.
'opc-life-over': The optical photo conductor is no longer
functioning.
'developer-low': The device is low on developer.
'developer-empty: The device is out of developer.
'interpreter-resource-unavailable': An interpreter resource is
unavailable (i.e. font, form)
4.4.12 printer-state-message (text(MAX))
This Printer attribute specifies the additional information about the
printer state and printer state reasons in human readable text. If
the Printer object supports this attribute, the Printer object MUST
be able to generate this message in any of the natural languages
identified by the Printer's "generated-natural-language-supported"
attribute (see the "attributes-natural-language" operation attribute
specified in Section 3.1.4.1).
4.4.13 operations-supported (1setOf type2 enum)
This REQUIRED Printer attribute specifies the set of supported
operations for this Printer object and contained Job objects. All
32-bit enum values for this attribute MUST NOT exceed 0x8FFF, since
these values are passed in two octets in each Protocol request
[RFC2565].
The following standard enum and "operation-id" (see section 3.1.2)
values are defined:
Value Operation Name
----------------- -------------------------------------
0x0000 reserved, not used
0x0001 reserved, not used
0x0002 Print-Job
0x0003 Print-URI
0x0004 Validate-Job
0x0005 Create-Job
0x0006 Send-Document
0x0007 Send-URI
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0x0008 Cancel-Job
0x0009 Get-Job-Attributes
0x000A Get-Jobs
0x000B Get-Printer-Attributes
0x000C-0x3FFF reserved for future operations
0x4000-0x8FFF reserved for private extensions
This allows for certain vendors to implement private extensions that
are guaranteed to not conflict with future registered extensions.
However, there is no guarantee that two or more private extensions
will not conflict.
4.4.14 charset-configured (charset)
This REQUIRED Printer attribute identifies the charset that the
Printer object has been configured to represent 'text' and 'name'
Printer attributes that are set by the operator, system
administrator, or manufacturer, i.e., for "printer-name" (name),
"printer-location" (text), "printer-info" (text), and "printer-make-
and-model" (text). Therefore, the value of the Printer object's
"charset-configured" attribute MUST also be among the values of the
Printer object's "charset-supported" attribute.
4.4.15 charset-supported (1setOf charset)
This REQUIRED Printer attribute identifies the set of charsets that
the Printer and contained Job objects support in attributes with
attribute syntax 'text' and 'name'. At least the value 'utf-8' MUST
be present, since IPP objects MUST support the UTF-8 [RFC2279]
charset. If a Printer object supports a charset, it means that for
all attributes of syntax 'text' and 'name' the IPP object MUST (1)
accept the charset in requests and return the charset in responses as
needed.
If more charsets than UTF-8 are supported, the IPP object MUST
perform charset conversion between the charsets as described in
Section 3.2.1.2.
4.4.16 natural-language-configured (naturalLanguage)
This REQUIRED Printer attribute identifies the natural language that
the Printer object has been configured to represent 'text' and 'name'
Printer attributes that are set by the operator, system
administrator, or manufacturer, i.e., for "printer-name" (name),
"printer-location" (text), "printer-info" (text), and "printer-make-
and-model" (text). When returning these Printer attributes, the
Printer object MAY return them in the configured natural language
specified by this attribute, instead of the natural language
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requested by the client in the "attributes-natural-language"
operation attribute. See Section 3.1.4.1 for the specification of
the OPTIONAL multiple natural language support. Therefore, the value
of the Printer object's "natural-language-configured" attribute MUST
also be among the values of the Printer object's "generated-natural-
language-supported" attribute.
4.4.17 generated-natural-language-supported (1setOf naturalLanguage)
This REQUIRED Printer attribute identifies the natural language(s)
that the Printer object and contained Job objects support in
attributes with attribute syntax 'text' and 'name'. The natural
language(s) supported depends on implementation and/or configuration.
Unlike charsets, IPP objects MUST accept requests with any natural
language or any Natural Language Override whether the natural
language is supported or not.
If a Printer object supports a natural language, it means that for
any of the attributes for which the Printer or Job object generates
messages, i.e., for the "job-state-message" and "printer-state-
message" attributes and Operation Messages (see Section 3.1.5) in
operation responses, the Printer and Job objects MUST be able to
generate messages in any of the Printer's supported natural
languages. See section 3.1.4 for the specification of 'text' and '
name' attributes in operation requests and responses.
Note: A Printer object that supports multiple natural languages,
often has separate catalogs of messages, one for each natural
language supported.
4.4.18 document-format-default (mimeMediaType)
This REQUIRED Printer attribute identifies the document format that
the Printer object has been configured to assume if the client does
not supply a "document-format" operation attribute in any of the
operation requests that supply document data. The standard values
for this attribute are Internet Media types (sometimes called MIME
types). For further details see the description of the '
mimeMediaType' attribute syntax in Section 4.1.9.
4.4.19 document-format-supported (1setOf mimeMediaType)
This REQUIRED Printer attribute identifies the set of document
formats that the Printer object and contained Job objects can
support. For further details see the description of the '
mimeMediaType' attribute syntax in Section 4.1.9.
4.4.20 printer-is-accepting-jobs (boolean)
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This REQUIRED Printer attribute indicates whether the printer is
currently able to accept jobs, i.e., is accepting Print-Job, Print-
URI, and Create-Job requests. If the value is 'true', the printer is
accepting jobs. If the value is 'false', the Printer object is
currently rejecting any jobs submitted to it. In this case, the
Printer object returns the 'server-error-not-accepting-jobs' status
code.
Note: This value is independent of the "printer-state" and "printer-
state-reasons" attributes because its value does not affect the
current job; rather it affects future jobs. This attribute may cause
the Printer to reject jobs when the "printer-state" is 'idle' or it
may cause the Printer object to accepts jobs when the "printer-state"
is 'stopped'.
4.4.21 queued-job-count (integer(0:MAX))
This RECOMMENDED Printer attribute contains a count of the number of
jobs that are either 'pending', 'processing', 'pending-held', or '
processing-stopped' and is set by the Printer object.
4.4.22 printer-message-from-operator (text(127))
This Printer attribute provides a message from an operator, system
administrator or "intelligent" process to indicate to the end user
information or status of the printer, such as why it is unavailable
or when it is expected to be available.
4.4.23 color-supported (boolean)
This Printer attribute identifies whether the device is capable of
any type of color printing at all, including highlight color. All
document instructions having to do with color are embedded within the
document PDL (none are external IPP attributes in IPP/1.0).
Note: end-users are able to determine the nature and details of the
color support by querying the "printer-more-info-manufacturer"
Printer attribute.
4.4.24 reference-uri-schemes-supported (1setOf uriScheme)
This Printer attribute specifies which URI schemes are supported for
use in the "document-uri" operation attribute of the Print-URI or
Send-URI operation. If a Printer object supports these optional
operations, it MUST support the "reference-uri-schemes-supported"
Printer attribute with at least the following schemed URI value:
'ftp': The Printer object will use an FTP 'get' operation as
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defined in RFC 2228 [RFC2228] using FTP URLs as defined by
[RFC2396] and[RFC2316].
The Printer object MAY OPTIONALLY support other URI schemes (see
section 4.1.6).
4.4.25 pdl-override-supported (type2 keyword)
This REQUIRED Printer attribute expresses the ability for a
particular Printer implementation to either attempt to override
document data instructions with IPP attributes or not.
This attribute takes on the following values:
- 'attempted': This value indicates that the Printer object
attempts to make the IPP attribute values take precedence over
embedded instructions in the document data, however there is no
guarantee.
- 'not-attempted': This value indicates that the Printer object
makes no attempt to make the IPP attribute values take precedence
over embedded instructions in the document data.
Section 15 contains a full description of how this attribute
interacts with and affects other IPP attributes, especially the
"ipp-attribute-fidelity" attribute.
4.4.26 printer-up-time (integer(1:MAX))
This REQUIRED Printer attribute indicates the amount of time (in
seconds) that this instance of this Printer implementation has been
up and running. This value is used to populate the Job attributes
"time-at-creation", "time-at-processing", and "time-at-completed".
These time values are all measured in seconds and all have meaning
only relative to this attribute, "printer-up-time". The value is a
monotonically increasing value starting from 1 when the Printer
object is started-up (initialized, booted, etc.).
If the Printer object goes down at some value 'n', and comes back up,
the implementation MAY:
1. Know how long it has been down, and resume at some value greater
than 'n', or
2. Restart from 1.
In the first case, the Printer SHOULD not tweak any existing related
Job attributes ("time-at-creation", "time-at-processing", and "time-
at-completed"). In the second case, the Printer object SHOULD reset
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those attributes to 0. If a client queries a time-related Job
attribute and finds the value to be 0, the client MUST assume that
the Job was submitted in some life other than the Printer's current
life.
4.4.27 printer-current-time (dateTime)
This Printer attribute indicates the current absolute wall-clock
time. If an implementation supports this attribute, then a client
could calculate the absolute wall-clock time each Job's "time-at-
creation", "time-at-processing", and "time-at-completed" attributes
by using both "printer-up-time" and this attribute, "printer-
current-time". If an implementation does not support this attribute,
a client can only calculate the relative time of certain events based
on the REQUIRED "printer-up-time" attribute.
4.4.28 multiple-operation-time-out (integer(1:MAX))
This Printer attributes identifies the minimum time (in seconds) that
the Printer object waits for additional Send-Document or Send-URI
operations to follow a still-open multi-document Job object before
taking any recovery actions, such as the ones indicated in section
3.3.1.
It is RECOMMENDED that vendors supply a value for this attribute that
is between 60 and 240 seconds. An implementation MAY allow a system
administrator to set this attribute. If so, the system administrator
MAY be able to set values outside this range.
4.4.29 compression-supported (1setOf type3 keyword)
This Printer attribute identifies the set of supported compression
algorithms for document data. Compression only applies to the
document data; compression does not apply to the encoding of the IPP
operation itself. The supported values are used to validate the
client supplied "compression" operation attributes in Print-Job,
Send-Document, and Send-URI requests.
Standard values are :
'none': no compression is used.
'deflate': ZIP public domain inflate/deflate) compression
technology
'gzip' GNU zip compression technology described in RFC 1952
[RFC1952].
'compress': UNIX compression technology
4.4.30 job-k-octets-supported (rangeOfInteger(0:MAX))
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This Printer attribute specifies the upper and lower bounds of total
sizes of jobs in K octets, i.e., in units of 1024 octets. The
supported values are used to validate the client supplied "job-k-
octets" operation attributes in create requests. The corresponding
job description attribute "job-k-octets" is defined in section
4.3.17.
4.4.31 job-impressions-supported (rangeOfInteger(0:MAX))
This Printer attribute specifies the upper and lower bounds for the
number of impressions per job. The supported values are used to
validate the client supplied "job-impressions" operation attributes
in create requests. The corresponding job description attribute
"job-impressions" is defined in section 4.3.18.
4.4.32 job-media-sheets-supported (rangeOfInteger(0:MAX))
This Printer attribute specifies the upper and lower bounds for the
number of media sheets per job. The supported values are used to
validate the client supplied "job-media-sheets" operation attributes
in create requests. The corresponding Job attribute "job-media-
sheets" is defined in section 4.3.19.
5. Conformance
This section describes conformance issues and requirements. This
document introduces model entities such as objects, operations,
attributes, attribute syntaxes, and attribute values. These
conformance sections describe the conformance requirements which
apply to these model entities.
5.1 Client Conformance Requirements
A conforming client MUST support all REQUIRED operations as defined
in this document. For each attribute included in an operation
request, a conforming client MUST supply a value whose type and value
syntax conforms to the requirements of the Model document as
specified in Sections 3 and 4. A conforming client MAY supply any
registered extensions and/or private extensions in an operation
request, as long as they meet the requirements in Section 6.
Otherwise, there are no conformance requirements placed on the user
interfaces provided by IPP clients or their applications. For
example, one application might not allow an end user to submit
multiple documents per job, while another does. One application
might first query a Printer object in order to supply a graphical
user interface (GUI) dialogue box with supported and default values
whereas a different implementation might not.
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When sending a request, an IPP client NEED NOT supply any attributes
that are indicated as OPTIONALLY supplied by the client.
A client MUST be able to accept any of the attribute syntaxes defined
in Section 4.1, including their full range, that may be returned to
it in a response from a Printer object. In particular for each
attribute that the client supports whose attribute syntax is 'text',
the client MUST accept and process both the 'textWithoutLanguage' and
'textWithLanguage' forms. Similarly, for each attribute that the
client supports whose attribute syntax is 'name', the client MUST
accept and process both the 'nameWithoutLanguage' and '
nameWithLanguage' forms. For presentation purposes, truncation of
long attribute values is not recommended. A recommended approach
would be for the client implementation to allow the user to scroll
through long attribute values.
A query response may contain attribute groups, attributes, and values
that the client does not expect. Therefore, a client implementation
MUST gracefully handle such responses and not refuse to inter-operate
with a conforming Printer that is returning extended registered or
private attributes and/or attribute values that conform to Section 6.
Clients may choose to ignore any parameters, attributes, or values
that they do not understand.
5.2 IPP Object Conformance Requirements
This section specifies the conformance requirements for conforming
implementations with respect to objects, operations, and attributes.
5.2.1 Objects
Conforming implementations MUST implement all of the model objects as
defined in this specification in the indicated sections:
Section 2.1 - Printer Object
Section 2.2 - Job Object
5.2.2 Operations
Conforming IPP object implementations MUST implement all of the
REQUIRED model operations, including REQUIRED responses, as defined
in this specification in the indicated sections:
For a Printer object:
Print-Job (section 3.2.1) REQUIRED
Print-URI (section 3.2.2) OPTIONAL
Validate-Job (section 3.2.3) REQUIRED
Create-Job (section 3.2.4) OPTIONAL
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Get-Printer-Attributes (section 3.2.5) REQUIRED
Get-Jobs (section 3.2.6) REQUIRED
For a Job object:
Send-Document (section 3.3.1) OPTIONAL
Send-URI (section 3.3.2) OPTIONAL
Cancel-Job (section 3.3.3) REQUIRED
Get-Job-Attributes (section 3.3.4) REQUIRED
Conforming IPP objects MUST support all REQUIRED operation attributes
and all values of such attributes if so indicated in the description.
Conforming IPP objects MUST ignore all unsupported or unknown
operation attributes or operation attribute groups received in a
request, but MUST reject a request that contains a supported
operation attribute that contains an unsupported value.
The following section on object attributes specifies the support
required for object attributes.
5.2.3 IPP Object Attributes
Conforming IPP objects MUST support all of the REQUIRED object
attributes, as defined in this specification in the indicated
sections.
If an object supports an attribute, it MUST support only those values
specified in this document or through the extension mechanism
described in section 5.2.4. It MAY support any non-empty subset of
these values. That is, it MUST support at least one of the specified
values and at most all of them.
5.2.4 Extensions
A conforming IPP object MAY support registered extensions and private
extensions, as long as they meet the requirements specified in
Section 6.
For each attribute included in an operation response, a conforming
IPP object MUST return a value whose type and value syntax conforms
to the requirement of the Model document as specified in Sections 3
and 4.
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5.2.5 Attribute Syntaxes
An IPP object MUST be able to accept any of the attribute syntaxes
defined in Section 4.1, including their full range, in any operation
in which a client may supply attributes or the system administrator
may configure attributes (by means outside the scope of IPP/1.0). In
particular for each attribute that the IPP object supports whose
attribute syntax is 'text', the IPP object MUST accept and process
both the 'textWithoutLanguage' and 'textWithLanguage' forms.
Similarly, for each attribute that the IPP object supports whose
attribute syntax is 'name', the IPP object MUST accept and process
both the 'nameWithoutLanguage' and 'nameWithLanguage' forms.
Furthermore, an IPP object MUST return attributes to the client in
operation responses that conform to the syntax specified in Section
4.1, including their full range if supplied previously by a client.
5.3 Charset and Natural Language Requirements
All clients and IPP objects MUST support the 'utf-8' charset as
defined in section 4.1.7.
IPP objects MUST be able to accept any client request which correctly
uses the "attributes-natural-language" operation attribute or the
Natural Language Override mechanism on any individual attribute
whether or not the natural language is supported by the IPP object.
If an IPP object supports a natural language, then it MUST be able to
translate (perhaps by table lookup) all generated 'text' or 'name'
attribute values into one of the supported languages (see section
3.1.4). That is, the IPP object that supports a natural language
NEED NOT be a general purpose translator of any arbitrary 'text' or '
name' value supplied by the client into that natural language.
However, the object MUST be able to translate (automatically
generate) any of its own attribute values and messages into that
natural language.
5.4 Security Conformance Requirements
Conforming IPP Printer objects MAY support Secure Socket Layer
Version 3 (SSL3) [SSL] access, support access without SSL3 or support
both means of access.
Conforming IPP clients SHOULD support SSL3 access and non-SSL3
access. Note: This client requirement to support both means that
conforming IPP clients will be able to inter-operate with any IPP
Printer object.
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For a detailed discussion of security considerations and the IPP
application security profile required for SSL3 support, see section
8.
6. IANA Considerations (registered and private extensions)
This section describes how IPP can be extended to allow the following
registered and private extensions to IPP:
1. keyword attribute values
2. enum attribute values
3. attributes
4. attribute syntaxes
5. operations
6. attribute groups
7. status codes
Extensions registered for use with IPP/1.0 are OPTIONAL for client
and IPP object conformance to the IPP/1.0 Model specification.
These extension procedures are aligned with the guidelines as set
forth by the IESG [RFC2434]. Section 11 describes how to propose new
registrations for consideration. IANA will reject registration
proposals that leave out required information or do not follow the
appropriate format described in Section 11. IPP/1.0 may also be
extended by an appropriate RFC that specifies any of the above
extensions.
6.1 Typed 'keyword' and 'enum' Extensions
IPP allows for 'keyword' and 'enum' extensions (see sections 4.1.2.3
and 4.1.4). This document uses prefixes to the 'keyword' and 'enum'
basic attribute syntax type in order to communicate extra information
to the reader through its name. This extra information is not
represented in the protocol because it is unimportant to a client or
Printer object. The list below describes the prefixes and their
meaning.
"type1": The IPP specification must be revised to add a new
keyword or a new enum. No private keywords or enums are
allowed.
"type2": Implementers can, at any time, add new keyword or enum
values by proposing the complete specification to IANA:
iana@iana.org
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IANA will forward the registration proposal to the IPP
Designated Expert who will review the proposal with a mailing
list that the Designated Expert keeps for this purpose.
Initially, that list will be the mailing list used by the IPP
WG:
ipp@pwg.org
even after the IPP WG is disbanded as permitted by [RFC2434].
The IPP Designated Expert is appointed by the IESG Area Director
responsible for IPP, according to [RFC2434].
When a type2 keyword or enum is approved, the IPP Designated
Expert becomes the point of contact for any future maintenance
that might be required for that registration.
"type3": Implementers can, at any time, add new keyword and enum
values by submitting the complete specification to IANA as for
type2 who will forward the proposal to the IPP Designated
Expert. While no additional technical review is required, the
IPP Designated Expert may, at his/her discretion, forward the
proposal to the same mailing list as for type2 registrations for
advice and comment.
When a type3 keyword or enum is approved by the IPP Designated
Expert, the original proposer becomes the point of contact for
any future maintenance that might be required for that
registration.
For type2 and type3 keywords, the proposer includes the name of the
keyword in the registration proposal and the name is part of the
technical review.
After type2 and type3 enums specifications are approved, the IPP
Designated Expert in consultation with IANA assigns the next
available enum number for each enum value.
IANA will publish approved type2 and type3 keyword and enum
attributes value registration specifications in:
ftp.isi.edu/iana/assignments/ipp/attribute-values/xxx/yyy.txt
where xxx is the attribute name that specifies the initial values and
yyy.txt is a descriptive file name that contains one or more enums or
keywords approved at the same time. For example, if several
additional enums for stapling are approved for use with the
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"finishings" attribute (and "finishings-default" and "finishings-
supported" attributes), IANA will publish the additional values in
the file:
ftp.isi.edu/iana/assignments/ipp/attribute-
values/finishings/stapling.txt
Note: Some attributes are defined to be: 'type3 keywords' | 'name'
which allows for attribute values to be extended by a site
administrator with administrator defined names. Such names are not
registered with IANA.
By definition, each of the three types above assert some sort of
registry or review process in order for extensions to be considered
valid. Each higher numbered level (1, 2, 3) tends to be decreasingly
less stringent than the previous level. Therefore, any typeN value
MAY be registered using a process for some typeM where M is less than
N, however such registration is NOT REQUIRED. For example, a type3
value MAY be registered in a type 1 manner (by being included in a
future version of an IPP specification), however, it is NOT REQUIRED.
This specification defines keyword and enum values for all of the
above types, including type3 keywords.
For private (unregistered) keyword extensions, implementers SHOULD
use keywords with a suitable distinguishing prefix, such as "xxx-"
where xxx is the (lowercase) fully qualified company name registered
with IANA for use in domain names [RFC1035]. For example, if the
company XYZ Corp. had obtained the domain name "XYZ.com", then a
private keyword 'abc' would be: 'xyz.com-abc'.
Note: RFC 1035 [RFC1035] indicates that while upper and lower case
letters are allowed in domain names, no significance is attached to
the case. That is, two names with the same spelling but different
case are to be treated as if identical. Also, the labels in a domain
name must follow the rules for ARPANET host names: They must start
with a letter, end with a letter or digit, and have as interior
characters only letters, digits, and hyphen. Labels must be 63
characters or less. Labels are separated by the "." character.
For private (unregistered) enum extension, implementers MUST use
values in the reserved integer range which is 2**30 to 2**31-1.
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6.2 Attribute Extensibility
Attribute names are type2 keywords. Therefore, new attributes may be
registered and have the same status as attributes in this document by
following the type2 extension rules. For private (unregistered)
attribute extensions, implementers SHOULD use keywords with a
suitable distinguishing prefix as described in Section 6.1.
IANA will publish approved attribute registration specifications as
separate files:
ftp.isi.edu/iana/assignments/ipp/attributes/xxx-yyy.txt
where "xxx-yyy" is the new attribute name.
If a new Printer object attribute is defined and its values can be
affected by a specific document format, its specification needs to
contain the following sentence:
"The value of this attribute returned in a Get-Printer-Attributes
response MAY depend on the "document-format" attribute supplied
(see Section 3.2.5.1)."
If the specification does not, then its value in the Get-Printer-
Attributes response MUST NOT depend on the "document-format" supplied
in the request. When a new Job Template attribute is registered, the
value of the Printer attributes MAY vary with "document-format"
supplied in the request without the specification having to indicate
so.
6.3 Attribute Syntax Extensibility
Attribute syntaxes are like type2 enums. Therefore, new attribute
syntaxes may be registered and have the same status as attribute
syntaxes in this document by following the type2 extension rules
described in Section 6.1. The value codes that identify each of the
attribute syntaxes are assigned in the Encoding and Transport
specification [RFC2565], including a designated range for private,
experimental use.
For attribute syntaxes, the IPP Designated Expert in consultation
with IANA assigns the next attribute syntax code in the appropriate
range as specified in [RFC2565]. IANA will publish approved
attribute syntax registration specifications as separate files:
ftp.isi.edu/iana/assignments/ipp/attribute-syntaxes/xxx-yyy.txt
where 'xxx-yyy' is the new attribute syntax name.
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6.4 Operation Extensibility
Operations may also be registered following the type2 procedures
described in Section 6.1, though major new operations will usually be
done by a new standards track RFC that augments this document. For
private (unregistered) operation extensions, implementers MUST use
the range for the "operation-id" in requests specified in Section
4.4.13 "operations-supported" Printer attribute.
For operations, the IPP Designated Expert in consultation with IANA
assigns the next operation-id code as specified in Section 4.4.13.
IANA will publish approved operation registration specifications as
separate files:
ftp.isi.edu/iana/assignments/ipp/operations/Xxx-Yyy.txt
where "Xxx-Yyy" is the new operation name.
6.5 Attribute Groups
Attribute groups passed in requests and responses may be registered
following the type2 procedures described in Section 6.1. The tags
that identify each of the attribute groups are assigned in [RFC2565].
For attribute groups, the IPP Designated Expert in consultation with
IANA assigns the next attribute group tag code in the appropriate
range as specified in [RFC2565]. IANA will publish approved
attribute group registration specifications as separate files:
ftp.isi.edu/iana/assignments/ipp/attribute-group-tags/xxx-yyy-
tag.txt
where 'xxx-yyy-tag' is the new attribute group tag name.
6.6 Status Code Extensibility
Operation status codes may also be registered following the type2
procedures described in Section 6.1. The values for status codes are
allocated in ranges as specified in Section 13 for each status code
class:
"informational" - Request received, continuing process
"successful" - The action was successfully received, understood,
and accepted
"redirection" - Further action must be taken in order to complete
the request
"client-error" - The request contains bad syntax or cannot be
fulfilled
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"server-error" - The IPP object failed to fulfill an apparently
valid request
For private (unregistered) operation status code extensions,
implementers MUST use the top of each range as specified in Section
13.
For operation status codes, the IPP Designated Expert in consultation
with IANA assigns the next status code in the appropriate class range
as specified in Section 13. IANA will publish approved status code
registration specifications as separate files:
ftp.isi.edu/iana/assignments/ipp/status-codes/xxx-yyy.txt
where "xxx-yyy" is the new operation status code keyword.
6.7 Registration of MIME types/sub-types for document-formats
The "document-format" attribute's syntax is 'mimeMediaType'. This
means that valid values are Internet Media Types (see Section 4.1.9).
RFC 2045 [RFC2045] defines the syntax for valid Internet media types.
IANA is the registry for all Internet media types.
6.8 Registration of charsets for use in 'charset' attribute values
The "attributes-charset" attribute's syntax is 'charset'. This means
that valid values are charsets names. When a charset in the IANA
registry has more than one name (alias), the name labeled as
"(preferred MIME name)", if present, MUST be used (see Section
4.1.7). IANA is the registry for charsets following the procedures
of [RFC2278].
7. Internationalization Considerations
Some of the attributes have values that are text strings and names
which are intended for human understanding rather than machine
understanding (see the 'text' and 'name' attribute syntaxes in
Sections 4.1.1 and 4.1.2).
In each operation request, the client
- identifies the charset and natural language of the request which
affects each supplied 'text' and 'name' attribute value, and
- requests the charset and natural language for attributes returned
by the IPP object in operation responses (as described in Section
3.1.4.1).
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In addition, the client MAY separately and individually identify the
Natural Language Override of a supplied 'text' or 'name' attribute
using the 'textWithLanguage' and 'nameWithLanguage' technique
described section 4.1.1.2 and 4.1.2.2 respectively.
All IPP objects MUST support the UTF-8 [RFC2279] charset in all '
text' and 'name' attributes supported. If an IPP object supports
more than the UTF-8 charset, the object MUST convert between them in
order to return the requested charset to the client according to
Section 3.1.4.2. If an IPP object supports more than one natural
language, the object SHOULD return 'text' and 'name' values in the
natural language requested where those values are generated by the
Printer (see Section 3.1.4.1).
For Printers that support multiple charsets and/or multiple natural
languages in 'text' and 'name' attributes, different jobs may have
been submitted in differing charsets and/or natural languages. All
responses MUST be returned in the charset requested by the client.
However, the Get-Jobs operation uses the 'textWithLanguage' and '
nameWithLanguage' mechanism to identify the differing natural
languages with each job attribute returned.
The Printer object also has configured charset and natural language
attributes. The client can query the Printer object to determine
the list of charsets and natural languages supported by the Printer
object and what the Printer object's configured values are. See the
"charset-configured", "charset-supported", "natural-language-
configured", and "generated-natural-language-supported" Printer
description attributes for more details.
The "charset-supported" attributed identifies the supported charsets.
If a charset is supported, the IPP object MUST be capable of
converting to and from that charset into any other supported charset.
In many cases, an IPP object will support only one charset and it
MUST be the UTF-8 charset.
The "charset-configured" attribute identifies the one supported
charset which is the native charset given the current configuration
of the IPP object (administrator defined).
The "generated-natural-language-supported" attribute identifies the
set of supported natural languages for generated messages; it is not
related to the set of natural languages that must be accepted for
client supplied 'text' and 'name' attributes. For client supplied '
text' and 'name' attributes, an IPP object MUST accept ALL supplied
natural languages. Just because a Printer object is currently
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configured to support 'en-us' natural language does not mean that the
Printer object should reject a job if the client supplies a job name
that is in 'fr-ca'.
The "natural-language-configured" attribute identifies the one
supported natural language for generated messages which is the native
natural language given the current configuration of the IPP object
(administrator defined).
Attributes of type 'text' and 'name' are populated from different
sources. These attributes can be categorized into following groups
(depending on the source of the attribute):
1. Some attributes are supplied by the client (e.g., the client
supplied "job-name", "document-name", and "requesting-user-name"
operation attributes along with the corresponding Job object's
"job-name" and "job-originating-user-name" attributes). The IPP
object MUST accept these attributes in any natural language no
matter what the set of supported languages for generated
messages
2. Some attributes are supplied by the system administrator (e.g.,
the Printer object's "printer-name" and "printer-location"
attributes). These too can be in any natural language. If the
natural language for these attributes is different than what a
client requests, then they must be reported using the Natural
Language Override mechanism.
3. Some attributes are supplied by the device manufacturer (e.g.,
the Printer object's "printer-make-and-model" attribute). These
too can be in any natural language. If the natural language for
these attributes is different than what a client requests, then
they must be reported using the Natural Language Override
mechanism.
4. Some attributes are supplied by the operator (e.g., the Job
object's "job-message-from-operator" attribute). These too can
be in any natural language. If the natural language for these
attributes is different than what a client requests, then they
must be reported using the Natural Language Override mechanism.
5. Some attributes are generated by the IPP object (e.g., the Job
object's "job-state-message" attribute, the Printer object's
"printer-state-message" attribute, and the "status-message"
operation attribute). These attributes can only be in one of
the "generated-natural-language-supported" natural languages.
If a client requests some natural language for these attributes
other than one of the supported values, the IPP object SHOULD
respond using the value of the "natural-language-configured"
attribute (using the Natural Language Override mechanism if
needed).
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The 'text' and 'name' attributes specified in this version of this
document (additional ones will be registered according to the
procedures in Section 6) are:
Attributes Source
-------------------------- ----------
Operation Attributes
job-name (name) client
document-name (name) client
requesting-user-name (name) client
status-message Job or Printer object
Job Template Attributes:
job-hold-until) client matches administrator-configured
(keyword | name
job-hold-until-default client matches administrator-configured
(keyword | name)
job-hold-until-supported client matches administrator-configured
(keyword | name)
job-sheets client matches administrator-configured
(keyword | name)
job-sheets-default client matches administrator-configured
(keyword | name)
job-sheets-supported client matches administrator-configured
(keyword | name)
media client matches administrator-configured
(keyword | name)
media-default client matches administrator-configured
(keyword | name)
media-supported client matches administrator-configured
(keyword | name)
media-ready client matches administrator-configured
(keyword | name)
Job Description Attributes:
job-name (name) client or Printer object
job-originating-user-name (name) Printer object
job-state-message (text) Job or Printer object
output-device-assigned (name(127)) administrator
job-message-from-operator (text(127)) operator
Printer Description Attributes:
printer-name (name(127)) administrator
printer-location (text(127)) administrator
printer-info (text(127)) administrator
printer-make-and-model (text(127)) administrator or manufacturer
printer-state-message (text) Printer object
printer-message-from-operator (text(127)) operator
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8. Security Considerations
Some IPP objects MAY be deployed over protocol stacks that support
Secure Socket Layer Version 3 (SSL3) [SSL]. Note: SSL3 is not an
IETF standards track specification. Other IPP objects MAY be
deployed over protocol stacks that do not support SSL3. Some IPP
objects MAY be deployed over both types of protocol stacks. Those
IPP objects that support SSL3, are capable of supporting mutual
authentication as well as privacy of messages via multiple encryption
schemes. An important point about security related information for
SSL3 access to an IPP object, is that the security-related parameters
(authentication, encryption keys, etc.) are "out-of-band" to the
actual IPP protocol.
An IPP object that does not support SSL3 MAY elect to support a
transport layer that provides other security mechanisms. For
example, in a mapping of IPP over HTTP/1.1 [RFC2565], if the IPP
object does not support SSL3, HTTP still allows for client
authentication using Digest Access Authentication (DAA) [RFC2069].
It is difficult to anticipate the security risks that might exist in
any given IPP environment. For example, if IPP is used within a given
corporation over a private network, the risks of exposing document
data may be low enough that the corporation will choose not to use
encryption on that data. However, if the connection between the
client and the IPP object is over a public network, the client may
wish to protect the content of the information during transmission
through the network with encryption.
Furthermore, the value of the information being printed may vary from
one IPP environment to the next. Printing payroll checks, for
example, would have a different value than printing public
information from a file. There is also the possibly of denial-of-
service attacks, but denial-of-service attacks against printing
resources are not well understood and there is no published
precedents regarding this scenario.
Once the authenticated identity of the requester has been supplied to
the IPP object, the object uses that identity to enforce any
authorization policy that might be in place. For example, one site's
policy might be that only the job owner is allowed to cancel a job.
The details and mechanisms to set up a particular access control
policy are not part of IPP/1.0, and must be established via some
other type of administrative or access control framework. However,
there are operation status codes that allow an IPP server to return
information back to a client about any potential access control
violations for an IPP object.
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During a create operation, the client's identity is recorded in the
Job object in an implementation-defined attribute. This information
can be used to verify a client's identity for subsequent operations
on that Job object in order to enforce any access control policy that
might be in effect. See section 8.3 below for more details.
Since the security levels or the specific threats that any given IPP
system administrator may be concerned with cannot be anticipated, IPP
MUST be capable of operating with different security mechanisms and
security policies as required by the individual installation.
Security policies might vary from very strong, to very weak, to none
at all, and corresponding security mechanisms will be required. SSL3
supports the type of negotiated levels of security required by most,
if not all, potential IPP environments. IPP environments that require
no security can elect to deploy IPP objects that do not utilize the
optional SSL3 security mechanisms.
8.1 Security Scenarios
The following sections describe specific security attacks for IPP
environments. Where examples are provided they should be considered
illustrative of the environment and not an exhaustive set. Not all of
these environments will necessarily be addressed in initial
implementations of IPP.
8.1.1 Client and Server in the Same Security Domain
This environment is typical of internal networks where traditional
office workers print the output of personal productivity applications
on shared work-group printers, or where batch applications print
their output on large production printers. Although the identity of
the user may be trusted in this environment, a user might want to
protect the content of a document against such attacks as
eavesdropping, replaying or tampering.
8.1.2 Client and Server in Different Security Domains
Examples of this environment include printing a document created by
the client on a publicly available printer, such as at a commercial
print shop; or printing a document remotely on a business associate's
printer. This latter operation is functionally equivalent to sending
the document to the business associate as a facsimile. Printing
sensitive information on a Printer in a different security domain
requires strong security measures. In this environment authentication
of the printer is required as well as protection against unauthorized
use of print resources. Since the document crosses security domains,
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protection against eavesdropping and document tampering are also
required. It will also be important in this environment to protect
Printers against "spamming" and malicious document content.
8.1.3 Print by Reference
When the document is not stored on the client, printing can be done
by reference. That is, the print request can contain a reference, or
pointer, to the document instead of the actual document itself.
Standard methods currently do not exist for remote entities to
"assume" the credentials of a client for forwarding requests to a 3rd
party. It is anticipated that Print-By-Reference will be used to
access "public" documents and that sophisticated methods for
authenticating "proxies" will not be specified for version 1 of IPP.
8.2 URIs for SSL3 and non-SSL3 Access
As described earlier, an IPP object can support SSL3 access, non-SSL3
access, or both. The "printer-uri-supported" attribute contains the
Printer object's URI(s). Its companion attribute, "uri-security-
supported", identifies the security mechanism used for each URI
listed in the "printer-uri-supported" attribute. For each Printer
operation request, a client MUST supply only one URI in the
"printer-uri" operation attribute. In other words, even though the
Printer supports more than one URI, the client only interacts with
the Printer object using one if its URIs. This duality is not needed
for Job objects, since the Printer objects is the factory for Job
objects, and the Printer object will generate the correct URI for new
Job objects depending on the Printer object's security configuration.
8.3 The "requesting-user-name" (name(MAX)) Operation Attribute
Each operation MUST specify the user who is performing the operation
in both of the following two ways:
1) via the REQUIRED "requesting-user-name" operation attribute that
a client SHOULD supply in all operations. The client MUST obtain
the value for this attribute from an environmental or network
login name for the user, rather than allowing the user to supply
any value. If the client does not supply a value for
"requesting-user-name", the printer MUST assume that the client
is supplying some anonymous name, such as "anonymous".
2) via an authentication mechanism of the underlying transport
which may be configured to give no authentication information.
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There are six cases to consider:
a) the authentication mechanism gives no information, and the
client doesn't specify "requesting-user-name".
b) the authentication mechanism gives no information, but the
client specifies "requesting-user-name".
c) the authentication mechanism specifies a user which has no human
readable representation, and the client doesn't specify
"requesting-user-name".
d) the authentication mechanism specifies a user which has no human
readable representation, but the client specifies "requesting-
user-name".
e) the authentication mechanism specifies a user which has a human
readable representation. The Printer object ignores the
"requesting-user-name".
f) the authentication mechanism specifies a user who is trusted and
whose name means that the value of the "requesting-user-name",
which MUST be present, is treated as the authenticated name.
Note: Case "f" is intended for a tightly coupled gateway and server
to work together so that the "user" name is able to be that of the
gateway client and not that of the gateway. Because most, if not
all, system vendors will initially implement IPP via a gateway into
their existing print system, this mechanism is necessary unless the
authentication mechanism allows a gateway (client) to act on behalf
of some other client.
The user-name has two forms:
- one that is human readable: it is held in the REQUIRED "job-
originating-user-name" Job Description attribute which is set
during the job creation operations. It is used for presentation
only, such as returning in queries or printing on start sheets
- one for authorization: it is held in an undefined (by IPP) Job
object attribute which is set by the job creation operation. It
is used to authorize other operations, such as Send-Document,
Send-URI, Cancel-Job, to determine the user when the "my-jobs"
attribute is specified with Get-Jobs, and to limit what
attributes and values to return with Get-Job-Attributes and Get-
Jobs.
The human readable user name:
- is the value of the "requesting-user-name" for cases b, d and f.
- comes from the authentication mechanism for case e
- is some anonymous name, such as "anonymous" for cases a and c.
The user name used for authorization:
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- is the value of the "requesting-user-name" for cases b and f.
- comes from the authentication mechanism for cases c, d and e
- is some anonymous name, such as "anonymous" for case a.
The essence of these rules for resolving conflicting sources of
user-names is that a printer implementation is free to pick either
source as long as it achieves consistent results. That is, if a user
uses the same path for a series of requests, the requests MUST appear
to come from the same user from the standpoint of both the human-
readable user name and the user name for authorization. This rule
MUST continue to apply even if a request could be authenticated by
two or more mechanisms. It doesn't matter which of several
authentication mechanisms a Printer uses as long as it achieves
consistent results. If a client uses more than one authentication
mechanism, it is recommended that an administrator make all
credentials resolve to the same user and user-name as much as
possible.
8.4 Restricted Queries
In many IPP operations, a client supplies a list of attributes to be
returned in the response. For security reasons, an IPP object may be
configured not to return all attributes (or all values) that a client
requests. The job attributes returned MAY depend on whether the
requesting user is the same as the user that submitted the job. The
IPP object MAY even return none of the requested attributes. In such
cases, the status returned is the same as if the object had returned
all requested attributes. The client cannot tell by such a response
whether the requested attribute was present or absent on the object.
8.5 Queries on jobs submitted using non-IPP protocols
If the device that an IPP Printer is representing is able to accept
jobs using other job submission protocols in addition to IPP, it is
RECOMMENDED that such an implementation at least allow such "foreign"
jobs to be queried using Get-Jobs returning "job-id" and "job-uri" as
'unknown'. Such an implementation NEED NOT support all of the same
IPP job attributes as for IPP jobs. The IPP object returns the '
unknown' out-of-band value for any requested attribute of a foreign
job that is supported for IPP jobs, but not for foreign jobs.
It is further RECOMMENDED, that the IPP Printer generate "job-id" and
"job-uri" values for such "foreign jobs", if possible, so that they
may be targets of other IPP operations, such as Get-Job-Attributes
and Cancel-Job. Such an implementation also needs to deal with the
problem of authentication of such foreign jobs. One approach would
be to treat all such foreign jobs as belonging to users other than
the user of the IPP client. Another approach would be for the
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foreign job to belong to 'anonymous'. Only if the IPP client has
been authenticated as an operator or administrator of the IPP Printer
object, could the foreign jobs be queried by an IPP request.
Alternatively, if the security policy is to allow users to query
other users' jobs, then the foreign jobs would also be visible to an
end-user IPP client using Get-Jobs and Get-Job-Attributes.
8.6 IPP Security Application Profile for SSL3
The IPP application profile for SSL3 follows the "Secure Socket
Layer" requirement as documented in the SSL3 specification [SSL].
For interoperability, the SSL3 cipher suites are:
SSL_RSA_WITH_RC4_128_MD5
SSL_RSA_WITH_3DES_EDE_CBC_SHA
SSL_RSA_WITH_DES_CBC_SHA
SSL_RSA_EXPORT_WITH_RC4_40_MD5
SSL_RSA_EXPORT_WITH_RC2_CBC_40_MD5
SSL_RSA_WITH_NULL_MD5
Client implementations MUST NOT assume any other cipher suites are
supported by an IPP Printer object.
If a conforming IPP object supports SSL3, it MUST implement and
support the cipher suites listed above and MAY support additional
cipher suites.
A conforming IPP client SHOULD support SSL3 including the cipher
suites listed above. A conforming IPP client MAY support additional
cipher suites.
It is possible that due to certain government export restrictions
some non-compliant versions of this extension could be deployed.
Implementations wishing to inter-operate with such non-compliant
versions MAY offer the SSL_RSA_EXPORT_WITH_RC4_40_MD5 and
SSL_RSA_EXPORT_WITH_RC2_CBC_40_MD5 mechanisms. However, since 40 bit
ciphers are known to be vulnerable to attack by current technology,
any client which actives a 40 bit cipher MUST NOT indicate to the
user that the connection is completely secure from eavesdropping.
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9. References
[ASCII] Coded Character Set - 7-bit American Standard Code for
Information Interchange (ASCII), ANSI X3.4-1986. This
standard is the specification of the US-ASCII charset.
[HTPP] J. Barnett, K. Carter, R. DeBry, "Initial Draft -
Hypertext Printing Protocol - HTPP/1.0", October 1996.
ftp://ftp.pwg.org/pub/pwg/ipp/historic/htpp/
overview.ps.gz
[IANA-CS] IANA Registry of Coded Character Sets:
ftp://ftp.isi.edu/in-notes/iana/assignments/character-
sets
[IANA-MT] IANA Registry of Media Types: ftp://ftp.isi.edu/in-
notes/iana/assignments/media-types/
[ipp-iig] Hastings, T. and C. Manros, "Internet Printing
Protocol/1.0: Implementer's Guide", Work in Progress.
[ISO10646-1] ISO/IEC 10646-1:1993, "Information technology --
Universal Multiple-Octet Coded Character Set (UCS) -
Part 1: Architecture and Basic Multilingual Plane,
JTC1/SC2."
[ISO8859-1] ISO/IEC 8859-1:1987, "Information technology -- 8-bit
One-Byte Coded Character Set - Part 1: Latin Alphabet Nr
1", 1987, JTC1/SC2.
[ISO10175] ISO/IEC 10175 Document Printing Application (DPA), June
1996.
[LDPA] T. Hastings, S. Isaacson, M. MacKay, C. Manros, D. Taylor, P.
Zehler, "LDPA - Lightweight Document Printing
Application", October 1996,
ftp://ftp.pwg.org/pub/pwg/ipp/historic/ldpa/ldpa8.pdf.gz
[P1387.4] Kirk, M. (Editor), POSIX System Administration - Part 4:
Printing Interfaces, POSIX 1387.4 D8, 1994.
[PSIS] Herriot, R. (editor), X/Open A Printing System
Interoperability Specification (PSIS), August 1995.
[PWG] Printer Working Group, http://www.pwg.org.
[RFC1035] Mockapetris, P., "DOMAIN NAMES - IMPLEMENTATION AND
SPECIFICATION", STD 13, RFC 1035, November 1987.
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RFC 2566 IPP/1.0: Model and Semantics April 1999
[RFC1759] Smith, R., Wright, F., Hastings, T., Zilles, S. and J.
Gyllenskog, "Printer MIB", RFC 1759, March 1995.
[RFC1766] Alvestrand, H., "Tags for the Identification of
Languages", RFC 1766, March 1995.
[RFC1179] McLaughlin, L. (Editor), "Line Printer Daemon Protocol",
RFC 1179, August 1990.
[RFC1952] Deutsch, P., "GZIP file format specification version
4.3", RFC 1952, May 1996.
[RFC2045] Freed, N. and N. Borenstein, " Multipurpose Internet
Mail Extensions (MIME) Part One: Format of Internet
Message Bodies", RFC 2045, November 1996.
[RFC2046] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part Two: Media Types", RFC 2046,
November 1996.
[RFC2048] Freed, N., Klensin, J. and J. Postel, "Multipurpose
Internet Mail Extension (MIME) Part Four: Registration
Procedures", RFC 2048, November 1996.
[RFC2068] Fielding, R., Gettys, J., Mogul, J., Frystyk, H. AND T.
Berners-Lee, "Hypertext Transfer Protocol - HTTP/1.1",
RFC 2068, January 1997.
[RFC2069] Franks, J., Hallam-Baker, P., Hostetler, J., Leach, P.,
Luotonen, A., Sink, E. and L. Stewart, "An Extension to
HTTP: Digest Access Authentication", RFC 2069, January
1997.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2228] Horowitz, M. and S. Lunt, "FTP Security Extensions", RFC
2228, October 1997.
[RFC2277] Alvestrand, H., "IETF Policy on Character Sets and
Languages" RFC 2277, January 1998.
[RFC2278] Freed, N. and J. Postel: "IANA Charset Registration
Procedures", BCP 19, RFC 2278, January 1998.
[RFC2279] Yergeau, F., "UTF-8, a transformation format of ISO
10646", RFC 2279, January 1998.
deBry, et al. Experimental [Page 132]
RFC 2566 IPP/1.0: Model and Semantics April 1999
[RFC2316] Bellovin, S., "Report of the IAB Security Architecture
Workshop", RFC 2316, April 1998.
[RFC2396] Berners-Lee, T., Fielding, R. and L. Masinter, "Uniform
Resource Identifiers (URI): Generic Syntax", RFC 2396,
August 1998.
[RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 2434,
October 1998.
[RFC2565] Herriot, R., Butler, S., Moore, P. and R. Tuner
"Internet Printing Protocol/1.0: Encoding and
Transport", RFC 2565, April 1999.
[RFC2567] Wright, D., "Design Goals for an Internet Printing
Protocol", RFC 2567, April 1999.
[RFC2568] Zilles, S., "Rationale for the Structure and Model and
Protocol for the Internet Printing Protocol", RFC 2568,
April 1999.
[RFC2569] Herriot, R., Hastings, T., Jacobs, N. and J. Martin,
"Mapping between LPD and IPP Protocols", RFC 2569, April
1999.
[RFC2579] McCloghrie, K., Perkins, D. and J. Schoenwaelder,
"Textual Conventions for SMIv2", STD 58, RFC 2579, April
1999.
[SSL] Netscape, The SSL Protocol, Version 3, (Text version
3.02), November 1996.
[SWP] P. Moore, B. Jahromi, S. Butler, "Simple Web Printing
SWP/1.0", May 7, 1997,
ftp://ftp.pwg.org/pub/pwg/ipp/new_PRO/swp9705.pdf
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10. Authors' Addresses
Scott A. Isaacson (Editor)
Novell, Inc.
122 E 1700 S
Provo, UT 84606
Phone: 801-861-7366
Fax: 801-861-2517
EMail: sisaacson@novell.com
Tom Hastings
Xerox Corporation
737 Hawaii St.
El Segundo, CA 90245
Phone: 310-333-6413
Fax: 310-333-5514
EMail: hastings@cp10.es.xerox.com
Robert Herriot
Xerox Corporation
3400 Hillview Ave., Bldg #1
Palo Alto, CA 94304
Phone: 650-813-7696
Fax: 650-813-6860
EMail: robert.herriot@pahv.xerox.com
Roger deBry
Utah Valley State College
Orem, UT 84058
Phone: (801) 222-8000
EMail: debryro@uvsc.edu
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Patrick Powell
Astart Technologies
9475 Chesapeake Dr., Suite D
San Diego, CA 95123
Phone: (619) 874-6543
Fax: (619) 279-8424
EMail: papowell@astart.com
IPP Mailing List: ipp@pwg.org
IPP Mailing List Subscription: ipp-request@pwg.org
IPP Web Page: http://www.pwg.org/ipp/
Implementers of this specification are encouraged to join IPP Mailing
List in order to participate in any discussions of clarification
issues and review of registration proposals for additional attributes
and values.
Other Participants:
Chuck Adams - Tektronix
Jeff Barnett - IBM
Ron Bergman - Dataproducts Corp.
Sylvan Butler - HP
Keith Carter - IBM Corporation
Jeff Copeland - QMS
Andy Davidson - Tektronix
Mabry Dozier - QMS
Lee Farrell - Canon Information Systems
Steve Gebert - IBM
Babek Jahromi - Microsoft
David Kellerman - Northlake Software
Rick Landau - Digital
Greg LeClair - Epson
Harry Lewis - IBM
Pete Loya - HP
Ray Lutz - Cognisys
Mike MacKay - Novell, Inc.
Daniel Manchala - Xerox
Carl-Uno Manros - Xerox
Jay Martin - Underscore
Larry Masinter - Xerox
Stan McConnell - Xerox
Ira McDonald - High North Inc.
Paul Moore - Microsoft
Tetsuya Morita - Ricoh
Yuichi Niwa - Ricoh
Pat Nogay - IBM
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Ron Norton - Printronics
Bob Pentecost - HP
Rob Rhoads - Intel
Xavier Riley - Xerox
David Roach - Unisys
Stuart Rowley - Kyocera
Hiroyuki Sato - Canon
Bob Setterbo - Adobe
Devon Taylor - Novell, Inc.
Mike Timperman - Lexmark
Randy Turner - Sharp
Atsushi Yuki - Kyocera
Rick Yardumian - Xerox
Lloyd Young - Lexmark
Bill Wagner - DPI
Jim Walker - DAZEL
Chris Wellens - Interworking Labs
Rob Whittle - Novell, Inc.
Don Wright - Lexmark
Peter Zehler - Xerox
Steve Zilles - Adobe
11. Formats for IPP Registration Proposals
In order to propose an IPP extension for registration, the proposer
must submit an application to IANA by email to "iana@iana.org" or by
filling out the appropriate form on the IANA web pages
(http://www.iana.org). This section specifies the required
information and the formats for proposing registrations of extensions
to IPP as provided in Section 6 for:
1. type2 'keyword' attribute values
2. type3 'keyword' attribute values
3. type2 'enum' attribute values
4. type3 'enum' attribute values
5. attributes
6. attribute syntaxes
7. operations
8. status codes
11.1 Type2 keyword attribute values registration
Type of registration: type2 keyword attribute value
Name of attribute to which this keyword specification is to be added:
Proposed keyword name of this keyword value:
Specification of this keyword value (follow the style of IPP Model
Section 4.1.2.3):
Name of proposer:
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Address of proposer:
Email address of proposer:
Note: For type2 keywords, the Designated Expert will be the point of
contact for the approved registration specification, if any
maintenance of the registration specification is needed.
11.2 Type3 keyword attribute values registration
Type of registration: type3 keyword attribute value
Name of attribute to which this keyword specification is to be added:
Proposed keyword name of this keyword value:
Specification of this keyword value (follow the style of IPP Model
Section 4.1.2.3):
Name of proposer:
Address of proposer:
Email address of proposer:
Note: For type3 keywords, the proposer will be the point of contact
for the approved registration specification, if any maintenance of
the registration specification is needed.
11.3 Type2 enum attribute values registration
Type of registration: type2 enum attribute value
Name of attribute to which this enum specification is to be added:
Keyword symbolic name of this enum value:
Numeric value (to be assigned by the IPP Designated Expert in
consultation with IANA):
Specification of this enum value (follow the style of IPP Model
Section 4.1.4):
Name of proposer:
Address of proposer:
Email address of proposer:
Note: For type2 enums, the Designated Expert will be the point of
contact for the approved registration specification, if any
maintenance of the registration specification is needed.
11.4 Type3 enum attribute values registration
Type of registration: type3 enum attribute value
Name of attribute to which this enum specification is to be added:
Keyword symbolic name of this enum value:
Numeric value (to be assigned by the IPP Designated Expert in
consultation with IANA):
Specification of this enum value (follow the style of IPP Model
Section 4.1.4):
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Name of proposer:
Address of proposer:
Email address of proposer:
Note: For type3 enums, the proposer will be the point of contact for
the approved registration specification, if any maintenance of the
registration specification is needed.
11.5 Attribute registration
Type of registration: attribute
Proposed keyword name of this attribute:
Types of attribute (Operation, Job Template, Job Description,
Printer Description):
Operations to be used with if the attribute is an operation
attribute:
Object (Job, Printer, etc. if bound to an object):
Attribute syntax(es) (include 1setOf and range as in Section 4.2):
If attribute syntax is 'keyword' or 'enum', is it type2 or type3:
If this is a Printer attribute, MAY the value returned depend on
"document-format" (See Section 6.2):
If this is a Job Template attribute, how does its specification
depend on the value of the "multiple-document-handling" attribute:
Specification of this attribute (follow the style of IPP Model
Section 4.2):
Name of proposer:
Address of proposer:
Email address of proposer:
Note: For attributes, the IPP Designated Expert will be the point of
contact for the approved registration specification, if any
maintenance of the registration specification is needed.
11.6 Attribute Syntax registration
Type of registration: attribute syntax
Proposed name of this attribute syntax:
Type of attribute syntax (integer, octetString, character-string,
see [RFC2565]):
Numeric value (to be assigned by the IPP Designated Expert in
consultation with IANA):
Specification of this attribute (follow the style of IPP Model
Section 4.1):
Name of proposer:
Address of proposer:
Email address of proposer:
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Note: For attribute syntaxes, the IPP Designated Expert will be the
point of contact for the approved registration specification, if any
maintenance of the registration specification is needed.
11.7 Operation registration
Type of registration: operation
Proposed name of this operation:
Numeric operation-id value (to be assigned by the IPP Designated
Expert in consultation with IANA):
Object Target (Job, Printer, etc. that operation is upon):
Specification of this attribute (follow the style of IPP Model
Section 3):
Name of proposer:
Address of proposer:
Email address of proposer:
Note: For operations, the IPP Designated Expert will be the point of
contact for the approved registration specification, if any
maintenance of the registration specification is needed.
11.8 Attribute Group registration
Type of registration: attribute group
Proposed name of this attribute group:
Numeric tag according to [RFC2565] (to be assigned by the IPP
Designated Expert in consultation with IANA):
Operation requests and group number for each operation in which the
attribute group occurs:
Operation responses and group number for each operation in which the
attribute group occurs:
Specification of this attribute group (follow the style of IPP Model
Section 3):
Name of proposer:
Address of proposer:
Email address of proposer:
Note: For attribute groups, the IPP Designated Expert will be the
point of contact for the approved registration specification, if any
maintenance of the registration specification is needed.
11.9 Status code registration
Type of registration: status code
Keyword symbolic name of this status code value:
Numeric value (to be assigned by the IPP Designated Expert in
consultation with IANA):
Operations that this status code may be used with:
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Specification of this status code (follow the style of IPP Model
Section 14 APPENDIX B: Status Codes and Suggested Status Code
Messages):
Name of proposer:
Address of proposer:
Email address of proposer:
Note: For status codes, the Designated Expert will be the point of
contact for the approved registration specification, if any
maintenance of the registration specification is needed.
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12. APPENDIX A: Terminology
This specification uses the terminology defined in this section.
12.1 Conformance Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHOULD", "SHOULD NOT",
"RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be
interpreted as described in RFC 2119 [RFC2119].
12.1.1 NEED NOT
This term is not included in RFC 2119. The verb "NEED NOT" indicates
an action that the subject of the sentence does not have to implement
in order to claim conformance to the standard. The verb "NEED NOT"
is used instead of "MAY NOT" since "MAY NOT" sounds like a
prohibition.
12.2 Model Terminology
12.2.1 Keyword
Keywords are used within this document as identifiers of semantic
entities within the abstract model (see section 4.1.2.3). Attribute
names, some attribute values, attribute syntaxes, and attribute group
names are represented as keywords.
12.2.2 Attributes
An attribute is an item of information that is associated with an
instance of an IPP object. An attribute consists of an attribute
name and one or more attribute values. Each attribute has a specific
attribute syntax. All object attributes are defined in section 4 and
all operation attributes are defined in section 3.
Job Template Attributes are described in section 4.2. The client
optionally supplies Job Template attributes in a create request
(operation requests that create Job objects). The Printer object has
associated attributes which define supported and default values for
the Printer.
12.2.2.1 Attribute Name
Each attribute is uniquely identified in this document by its
attribute name. An attribute name is a keyword. The keyword
attribute name is given in the section header describing that
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attribute. In running text in this document, attribute names are
indicated inside double quotation marks (") where the quotation marks
are not part of the keyword itself.
12.2.2.2 Attribute Group Name
Related attributes are grouped into named groups. The name of the
group is a keyword. The group name may be used in place of naming
all the attributes in the group explicitly. Attribute groups are
defined in section 3.
12.2.2.3 Attribute Value
Each attribute has one or more values. Attribute values are
represented in the syntax type specified for that attribute. In
running text in this document, attribute values are indicated inside
single quotation marks ('), whether their attribute syntax is
keyword, integer, text, etc. where the quotation marks are not part
of the value itself.
12.2.2.4 Attribute Syntax
Each attribute is defined using an explicit syntax type. In this
document, each syntax type is defined as a keyword with specific
meaning. The Encoding and Transport document [RFC2565] indicates the
actual "on-the-wire" encoding rules for each syntax type. Attribute
syntax types are defined in section 4.1.
12.2.3 Supports
By definition, a Printer object supports an attribute only if that
Printer object responds with the corresponding attribute populated
with some value(s) in a response to a query for that attribute. A
Printer object supports an attribute value if the value is one of the
Printer object's "supported values" attributes. The device behind a
Printer object may exhibit a behavior that corresponds to some IPP
attribute, but if the Printer object, when queried for that
attribute, doesn't respond with the attribute, then as far as IPP is
concerned, that implementation does not support that feature. If the
Printer object's "xxx-supported" attribute is not populated with a
particular value (even if that value is a legal value for that
attribute), then that Printer object does not support that particular
value.
A conforming implementation MUST support all REQUIRED attributes.
However, even for REQUIRED attributes, conformance to IPP does not
mandate that all implementations support all possible values
representing all possible job processing behaviors and features. For
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example, if a given instance of a Printer supports only certain
document formats, then that Printer responds with the "document-
format-supported" attribute populated with a set of values, possibly
only one, taken from the entire set of possible values defined for
that attribute. This limited set of values represents the Printer's
set of supported document formats. Supporting an attribute and some
set of values for that attribute enables IPP end users to be aware of
and make use of those features associated with that attribute and
those values. If an implementation chooses to not support an
attribute or some specific value, then IPP end users would have no
ability to make use of that feature within the context of IPP itself.
However, due to existing practice and legacy systems which are not
IPP aware, there might be some other mechanism outside the scope of
IPP to control or request the "unsupported" feature (such as embedded
instructions within the document data itself).
For example, consider the "finishings-supported" attribute.
1) If a Printer object is not physically capable of stapling, the
"finishings-supported" attribute MUST NOT be populated with the
value of 'staple'.
2) A Printer object is physically capable of stapling, however an
implementation chooses not to support stapling in the IPP
"finishings" attribute. In this case, 'staple' MUST NOT be a
value in the "finishings-supported" Printer object attribute.
Without support for the value 'staple', an IPP end user would
have no means within the protocol itself to request that a Job
be stapled. However, an existing document data formatter might
be able to request that the document be stapled directly with an
embedded instruction within the document data. In this case,
the IPP implementation does not "support" stapling, however the
end user is still able to have some control over the stapling of
the completed job.
3) A Printer object is physically capable of stapling, and an
implementation chooses to support stapling in the IPP
"finishings" attribute. In this case, 'staple' MUST be a value
in the "finishings-supported" Printer object attribute. Doing
so, would enable end users to be aware of and make use of the
stapling feature using IPP attributes.
Even though support for Job Template attributes by a Printer object
is OPTIONAL, it is RECOMMENDED that if the device behind a Printer
object is capable of realizing any feature or function that
corresponds to an IPP attribute and some associated value, then that
implementation SHOULD support that IPP attribute and value.
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The set of values in any of the supported value attributes is set
(populated) by some administrative process or automatic sensing
mechanism that is outside the scope of IPP. For administrative
policy and control reasons, an administrator may choose to make only
a subset of possible values visible to the end user. In this case,
the real output device behind the IPP Printer abstraction may be
capable of a certain feature, however an administrator is specifying
that access to that feature not be exposed to the end user through
the IPP protocol. Also, since a Printer object may represent a
logical print device (not just a physical device) the actual process
for supporting a value is undefined and left up to the
implementation. However, if a Printer object supports a value, some
manual human action may be needed to realize the semantic action
associated with the value, but no end user action is required.
For example, if one of the values in the "finishings-supported"
attribute is 'staple', the actual process might be an automatic
staple action by a physical device controlled by some command sent to
the device. Or, the actual process of stapling might be a manual
action by an operator at an operator attended Printer object.
For another example of how supported attributes function, consider a
system administrator who desires to control all print jobs so that no
job sheets are printed in order to conserve paper. To force no job
sheets, the system administrator sets the only supported value for
the "job-sheets-supported" attribute to 'none'. In this case, if a
client requests anything except 'none', the create request is
rejected or the "job-sheets" value is ignored (depending on the value
of "ipp-attribute-fidelity"). To force the use of job start/end
sheets on all jobs, the administrator does not include the value '
none' in the "job-sheets-supported" attribute. In this case, if a
client requests 'none', the create request is rejected or the "job-
sheets" value is ignored (again depending on the value of "ipp-
attribute-fidelity").
12.2.4 print-stream page
A "print-stream page" is a page according to the definition of pages
in the language used to express the document data.
12.2.5 impression
An "impression" is the image (possibly many print-stream pages in
different configurations) imposed onto a single media page.
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13. APPENDIX B: Status Codes and Suggested Status Code Messages
This section defines status code enum keywords and values that are
used to provide semantic information on the results of an operation
request. Each operation response MUST include a status code. The
response MAY also contain a status message that provides a short
textual description of the status. The status code is intended for
use by automata, and the status message is intended for the human end
user. Since the status message is an OPTIONAL component of the
operation response, an IPP application (i.e., a browser, GUI, print
driver or gateway) is NOT REQUIRED to examine or display the status
message, since it MAY not be returned to the application.
The prefix of the status keyword defines the class of response as
follows:
"informational" - Request received, continuing process
"successful" - The action was successfully received, understood,
and accepted
"redirection" - Further action must be taken in order to complete
the request
"client-error" - The request contains bad syntax or cannot be
fulfilled
"server-error" - The IPP object failed to fulfill an apparently
valid request
As with type2 enums, IPP status codes are extensible. IPP clients
are NOT REQUIRED to understand the meaning of all registered status
codes, though such understanding is obviously desirable. However,
IPP clients MUST understand the class of any status code, as
indicated by the prefix, and treat any unrecognized response as being
equivalent to the first status code of that class, with the exception
that an unrecognized response MUST NOT be cached. For example, if an
unrecognized status code of "client-error-xxx-yyy" is received by the
client, it can safely assume that there was something wrong with its
request and treat the response as if it had received a "client-
error-bad-request" status code. In such cases, IPP applications
SHOULD present the OPTIONAL message (if present) to the end user
since the message is likely to contain human readable information
which will help to explain the unusual status. The name of the enum
is the suggested status message for US English.
The status code values range from 0x0000 to 0x7FFF. The value ranges
for each status code class are as follows:
"successful" - 0x0000 to 0x00FF
"informational" - 0x0100 to 0x01FF
"redirection" - 0x0200 to 0x02FF
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"client-error" - 0x0400 to 0x04FF
"server-error" - 0x0500 to 0x05FF
The top half (128 values) of each range (0x0n40 to 0x0nFF, for n = 0
to 5) is reserved for private use within each status code class.
Values 0x0600 to 0x7FFF are reserved for future assignment and MUST
NOT be used.
13.1 Status Codes
Each status code is described below. Section 13.1.5.9 contains a
table that indicates which status codes apply to which operations.
The Implementer's Guide [ipp-iig] describe the suggested steps for
processing IPP attributes for all operations, including returning
status codes.
13.1.1 Informational
This class of status code indicates a provisional response and is to
be used for informational purposes only.
There are no status codes defined in IPP/1.0 for this class of status
code.
13.1.2 Successful Status Codes
This class of status code indicates that the client's request was
successfully received, understood, and accepted.
13.1.2.1 successful-ok (0x0000)
The request has succeeded and no request attributes were substituted
or ignored. In the case of a response to a create request, the '
successful-ok' status code indicates that the request was
successfully received and validated, and that the Job object has been
created; it does not indicate that the job has been processed. The
transition of the Job object into the 'completed' state is the only
indicator that the job has been printed.
13.1.2.2 successful-ok-ignored-or-substituted-attributes (0x0001)
The request has succeeded, but some supplied (1) attributes were
ignored or (2) unsupported values were substituted with supported
values or were ignored in order to perform the operation without
rejecting it. Unsupported attributes, attribute syntaxes, or values
MUST be returned in the Unsupported Attributes group of the response
for all operations. There is an exception to this rule for the query
operations: Get-Printer-Attributes, Get-Jobs, and Get-Job-Attributes
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for the "requested-attributes" operation attribute only. When the
supplied values of the "requested-attributes" operation attribute are
requesting attributes that are not supported, the IPP object MAY, but
is NOT REQUIRED to, return the "requested-attributes" attribute in
the Unsupported Attribute response group (with the unsupported values
only). See section 3.2.1.2.
13.1.2.3 successful-ok-conflicting-attributes (0x0002)
The request has succeeded, but some supplied attribute values
conflicted with the values of other supplied attributes. These
conflicting values were either (1) substituted with (supported)
values or (2) the attributes were removed in order to process the job
without rejecting it. Attributes or values which conflict with other
attributes and have been substituted or ignored MUST be returned in
the Unsupported Attributes group of the response for all operations
as supplied by the client. See section 3.2.1.2.
13.1.3 Redirection Status Codes
This class of status code indicates that further action needs to be
taken to fulfill the request.
There are no status codes defined in IPP/1.0 for this class of status
code.
13.1.4 Client Error Status Codes
This class of status code is intended for cases in which the client
seems to have erred. The IPP object SHOULD return a message
containing an explanation of the error situation and whether it is a
temporary or permanent condition.
13.1.4.1 client-error-bad-request (0x0400)
The request could not be understood by the IPP object due to
malformed syntax (such as the value of a fixed length attribute whose
length does not match the prescribed length for that attribute - see
the Implementer's Guide [ipp-iig] ). The IPP application SHOULD NOT
repeat the request without modifications.
13.1.4.2 client-error-forbidden (0x0401)
The IPP object understood the request, but is refusing to fulfill it.
Additional authentication information or authorization credentials
will not help and the request SHOULD NOT be repeated. This status
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code is commonly used when the IPP object does not wish to reveal
exactly why the request has been refused or when no other response is
applicable.
13.1.4.3 client-error-not-authenticated (0x0402)
The request requires user authentication. The IPP client may repeat
the request with suitable authentication information. If the request
already included authentication information, then this status code
indicates that authorization has been refused for those credentials.
If this response contains the same challenge as the prior response,
and the user agent has already attempted authentication at least
once, then the response message may contain relevant diagnostic
information. This status codes reveals more information than
"client-error-forbidden".
13.1.4.4 client-error-not-authorized (0x0403)
The requester is not authorized to perform the request. Additional
authentication information or authorization credentials will not help
and the request SHOULD NOT be repeated. This status code is used
when the IPP object wishes to reveal that the authentication
information is understandable, however, the requester is explicitly
not authorized to perform the request. This status codes reveals
more information than "client-error-forbidden" and "client-error-
not-authenticated".
13.1.4.5 client-error-not-possible (0x0404)
This status code is used when the request is for something that can
not happen. For example, there might be a request to cancel a job
that has already been canceled or aborted by the system. The IPP
client SHOULD NOT repeat the request.
13.1.4.6 client-error-timeout (0x0405)
The client did not produce a request within the time that the IPP
object was prepared to wait. For example, a client issued a Create-
Job operation and then, after a long period of time, issued a Send-
Document operation and this error status code was returned in
response to the Send-Document request (see section 3.3.1). The IPP
object might have been forced to clean up resources that had been
held for the waiting additional Documents. The IPP object was forced
to close the Job since the client took too long. The client SHOULD
NOT repeat the request without modifications.
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13.1.4.7 client-error-not-found (0x0406)
The IPP object has not found anything matching the request URI. No
indication is given of whether the condition is temporary or
permanent. For example, a client with an old reference to a Job (a
URI) tries to cancel the Job, however in the mean time the Job might
have been completed and all record of it at the Printer has been
deleted. This status code, 'client-error-not-found' is returned
indicating that the referenced Job can not be found. This error
status code is also used when a client supplies a URI as a reference
to the document data in either a Print-URI or Send-URI operation, but
the document can not be found.
In practice, an IPP application should avoid a not found situation by
first querying and presenting a list of valid Printer URIs and Job
URIs to the end-user.
13.1.4.8 client-error-gone (0x0407)
The requested object is no longer available and no forwarding address
is known. This condition should be considered permanent. Clients
with link editing capabilities should delete references to the
request URI after user approval. If the IPP object does not know or
has no facility to determine, whether or not the condition is
permanent, the status code "client-error-not-found" should be used
instead.
This response is primarily intended to assist the task of maintenance
by notifying the recipient that the resource is intentionally
unavailable and that the IPP object administrator desires that remote
links to that resource be removed. It is not necessary to mark all
permanently unavailable resources as "gone" or to keep the mark for
any length of time -- that is left to the discretion of the IPP
object administrator.
13.1.4.9 client-error-request-entity-too-large (0x0408)
The IPP object is refusing to process a request because the request
entity is larger than the IPP object is willing or able to process.
An IPP Printer returns this status code when it limits the size of
print jobs and it receives a print job that exceeds that limit or
when the attributes are so many that their encoding causes the
request entity to exceed IPP object capacity.
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13.1.4.10 client-error-request-value-too-long (0x0409)
The IPP object is refusing to service the request because one or more
of the client-supplied attributes has a variable length value that is
longer than the maximum length specified for that attribute. The IPP
object might not have sufficient resources (memory, buffers, etc.) to
process (even temporarily), interpret, and/or ignore a value larger
than the maximum length. Another use of this error code is when the
IPP object supports the processing of a large value that is less than
the maximum length, but during the processing of the request as a
whole, the object may pass the value onto some other system component
which is not able to accept the large value. For more details, see
the Implementer's Guide [ipp-iig] .
Note: For attribute values that are URIs, this rare condition is
only likely to occur when a client has improperly submitted a request
with long query information (e.g. an IPP application allows an end-
user to enter an invalid URI), when the client has descended into a
URI "black hole" of redirection (e.g., a redirected URI prefix that
points to a suffix of itself), or when the IPP object is under attack
by a client attempting to exploit security holes present in some IPP
objects using fixed-length buffers for reading or manipulating the
Request-URI.
13.1.4.11 client-error-document-format-not-supported (0x040A)
The IPP object is refusing to service the request because the
document data is in a format, as specified in the "document-format"
operation attribute, that is not supported by the Printer object.
This error is returned independent of the client-supplied "ipp-
attribute-fidelity". The Printer object MUST return this status
code, even if there are other attributes that are not supported as
well, since this error is a bigger problem than with Job Template
attributes.
13.1.4.12 client-error-attributes-or-values-not-supported (0x040B)
In a create request, if the Printer object does not support one or
more attributes, attribute syntaxes, or attribute values supplied in
the request and the client supplied the "ipp-attributes-fidelity"
operation attribute with the 'true' value, the Printer object MUST
return this status code. For example, if the request indicates '
iso-a4' media, but that media type is not supported by the Printer
object. Or, if the client supplies an optional attribute and the
attribute itself is not even supported by the Printer. If the "ipp-
attribute-fidelity" attribute is 'false', the Printer MUST ignore or
substitute values for unsupported attributes and values rather than
reject the request and return this status code.
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For any operation where a client requests attributes (such as a Get-
Jobs, Get-Printer-Attributes, or Get-Job-Attributes operation), if
the IPP object does not support one or more of the requested
attributes, the IPP object simply ignores the unsupported requested
attributes and processes the request as if they had not been
supplied, rather than returning this status code. In this case, the
IPP object MUST return the 'successful-ok-ignored-or-substituted-
attributes' status code and MAY return the unsupported attributes as
values of the "requested-attributes" in the Unsupported Attributes
Group (see section 13.1.2.2).
13.1.4.13 client-error-uri-scheme-not-supported (0x040C)
The type of the client supplied URI in a Print-URI or a Send-URI
operation is not supported.
13.1.4.14 client-error-charset-not-supported (0x040D)
For any operation, if the IPP Printer does not support the charset
supplied by the client in the "attributes-charset" operation
attribute, the Printer MUST reject the operation and return this
status and any 'text' or 'name' attributes using the 'utf-8' charset
(see Section 3.1.4.1).
13.1.4.15 client-error-conflicting-attributes (0x040E)
The request is rejected because some attribute values conflicted with
the values of other attributes which this specification does not
permit to be substituted or ignored.
13.1.5 Server Error Status Codes
This class of status codes indicates cases in which the IPP object is
aware that it has erred or is incapable of performing the request.
The IPP object SHOULD include a message containing an explanation of
the error situation, and whether it is a temporary or permanent
condition.
13.1.5.1 server-error-internal-error (0x0500)
The IPP object encountered an unexpected condition that prevented it
from fulfilling the request. This error status code differs from
"server-error-temporary-error" in that it implies a more permanent
type of internal error. It also differs from "server-error-device-
error" in that it implies an unexpected condition (unlike a paper-jam
or out-of-toner problem which is undesirable but expected). This
error status code indicates that probably some knowledgeable human
intervention is required.
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13.1.5.2 server-error-operation-not-supported (0x0501)
The IPP object does not support the functionality required to fulfill
the request. This is the appropriate response when the IPP object
does not recognize an operation or is not capable of supporting it.
13.1.5.3 server-error-service-unavailable (0x0502)
The IPP object is currently unable to handle the request due to a
temporary overloading or maintenance of the IPP object. The
implication is that this is a temporary condition which will be
alleviated after some delay. If known, the length of the delay may be
indicated in the message. If no delay is given, the IPP application
should handle the response as it would for a "server-error-
temporary-error" response. If the condition is more permanent, the
error status codes "client-error-gone" or "client-error-not-found"
could be used.
13.1.5.4 server-error-version-not-supported (0x0503)
The IPP object does not support, or refuses to support, the IPP
protocol version that was used in the request message. The IPP
object is indicating that it is unable or unwilling to complete the
request using the same version as supplied in the request other than
with this error message. The response should contain a Message
describing why that version is not supported and what other versions
are supported by that IPP object.
A conforming IPP/1.0 client MUST specify the valid version ('1.0') on
each request. A conforming IPP/1.0 object MUST NOT return this
status code to a conforming IPP/1.0 client. An IPP object MUST
return this status code to a non-conforming IPP client. The response
MUST identify in the "version-number" operation attribute the closest
version number that the IPP object does support.
13.1.5.5 server-error-device-error (0x0504)
A printer error, such as a paper jam, occurs while the IPP object
processes a Print or Send operation. The response contains the true
Job Status (the values of the "job-state" and "job-state-reasons"
attributes). Additional information can be returned in the optional
"job-state-message" attribute value or in the OPTIONAL status message
that describes the error in more detail. This error status code is
only returned in situations where the Printer is unable to accept the
create request because of such a device error. For example, if the
Printer is unable to spool, and can only accept one job at a time,
the reason it might reject a create request is that the printer
currently has a paper jam. In many cases however, where the Printer
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object can accept the request even though the Printer has some error
condition, the 'successful-ok' status code will be returned. In such
a case, the client would look at the returned Job Object Attributes
or later query the Printer to determine its state and state reasons.
13.1.5.6 server-error-temporary-error (0x0505)
A temporary error such as a buffer full write error, a memory
overflow (i.e. the document data exceeds the memory of the Printer),
or a disk full condition, occurs while the IPP Printer processes an
operation. The client MAY try the unmodified request again at some
later point in time with an expectation that the temporary internal
error condition may have been cleared. Alternatively, as an
implementation option, a Printer object MAY delay the response until
the temporary condition is cleared so that no error is returned.
13.1.5.7 server-error-not-accepting-jobs (0x0506)
A temporary error indicating that the Printer is not currently
accepting jobs, because the administrator has set the value of the
Printer's "printer-is-not-accepting-jobs" attribute to 'false' (by
means outside of IPP/1.0).
13.1.5.8 server-error-busy (0x0507)
A temporary error indicating that the Printer is too busy processing
jobs and/or other requests. The client SHOULD try the unmodified
request again at some later point in time with an expectation that
the temporary busy condition will have been cleared.
13.1.5.9 server-error-job-canceled (0x0508)
An error indicating that the job has been canceled by an operator or
the system while the client was transmitting the data to the IPP
Printer. If a job-id and job-uri had been created, then they are
returned in the Print-Job, Send-Document, or Send-URI response as
usual; otherwise, no job-id and job-uri are returned in the response.
13.2 Status Codes for IPP Operations
PJ = Print-Job, PU = Print-URI, CJ = Create-Job, SD = Send-Document
SU = Send-URI, V = Validate-Job, GA = Get-Job-Attributes and
Get-Printer-Attributes, GJ = Get-Jobs, C = Cancel-Job
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IPP Operations
IPP Status Keyword PJ PU CJ SD SU V GA GJ C
------------------ -- -- -- -- -- - -- -- -
successful-ok x x x x x x x x x
successful-ok-ignored-or-substituted- x x x x x x x x x
attributes
successful-ok-conflicting-attributes x x x x x x x x x
client-error-bad-request x x x x x x x x x
client-error-forbidden x x x x x x x x x
client-error-not-authenticated x x x x x x x x x
client-error-not-authorized x x x x x x x x x
client-error-not-possible x x x x x x x x x
client-error-timeout x x
client-error-not-found x x x x x x x x x
client-error-gone x x x x x x x x x
client-error-request-entity-too-large x x x x x x x x x
client-error-request-value-too-long x x x x x x x x x
client-error-document-format-not- x x x x x x
supported
client-error-attributes-or-values-not- x x x x x x x x x
supported
client-error-uri-scheme-not-supported x x
client-error-charset-not-supported x x x x x x x x x
client-error-conflicting-attributes x x x x x x x x x
server-error-internal-error x x x x x x x x x
server-error-operation-not-supported x x x x
server-error-service-unavailable x x x x x x x x x
server-error-version-not-supported x x x x x x x x x
server-error-device-error x x x x x
server-error-temporary-error x x x x x
server-error-not-accepting-jobs x x x x
server-error-busy x x x x x x x x x
server-error-job-canceled x x
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14. APPENDIX C: "media" keyword values
Standard keyword values are taken from several sources.
Standard values are defined (taken from DPA[ISO10175] and the Printer
MIB[RFC1759]):
'default': The default medium for the output device
'iso-a4-white': Specifies the ISO A4 white medium
'iso-a4-colored': Specifies the ISO A4 colored medium
'iso-a4-transparent' Specifies the ISO A4 transparent medium
'iso-a3-white': Specifies the ISO A3 white medium
'iso-a3-colored': Specifies the ISO A3 colored medium
'iso-a5-white': Specifies the ISO A5 white medium
'iso-a5-colored': Specifies the ISO A5 colored medium
'iso-b4-white': Specifies the ISO B4 white medium
'iso-b4-colored': Specifies the ISO B4 colored medium
'iso-b5-white': Specifies the ISO B5 white medium
'iso-b5-colored': Specifies the ISO B5 colored medium
'jis-b4-white': Specifies the JIS B4 white medium
'jis-b4-colored': Specifies the JIS B4 colored medium
'jis-b5-white': Specifies the JIS B5 white medium
'jis-b5-colored': Specifies the JIS B5 colored medium
The following standard values are defined for North American media:
'na-letter-white': Specifies the North American letter white medium
'na-letter-colored': Specifies the North American letter colored
medium
'na-letter-transparent': Specifies the North American letter
transparent medium
'na-legal-white': Specifies the North American legal white medium
'na-legal-colored': Specifies the North American legal colored
medium
The following standard values are defined for envelopes:
'iso-b4-envelope': Specifies the ISO B4 envelope medium
'iso-b5-envelope': Specifies the ISO B5 envelope medium
'iso-c3-envelope': Specifies the ISO C3 envelope medium
'iso-c4-envelope': Specifies the ISO C4 envelope medium
'iso-c5-envelope': Specifies the ISO C5 envelope medium
'iso-c6-envelope': Specifies the ISO C6 envelope medium
'iso-designated-long-envelope': Specifies the ISO Designated Long
envelope medium
'na-10x13-envelope': Specifies the North American 10x13 envelope
medium
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'na-9x12-envelope': Specifies the North American 9x12 envelope
medium
'monarch-envelope': Specifies the Monarch envelope
'na-number-10-envelope': Specifies the North American number 10
business envelope medium
'na-7x9-envelope': Specifies the North American 7x9 inch envelope
'na-9x11-envelope': Specifies the North American 9x11 inch envelope
'na-10x14-envelope': Specifies the North American 10x14 inch
envelope
'na-number-9-envelope': Specifies the North American number 9
business envelope
'na-6x9-envelope': Specifies the North American 6x9 inch envelope
'na-10x15-envelope': Specifies the North American 10x15 inch
envelope
The following standard values are defined for the less commonly used
media (white-only):
'executive-white': Specifies the white executive medium
'folio-white': Specifies the folio white medium
'invoice-white': Specifies the white invoice medium
'ledger-white': Specifies the white ledger medium
'quarto-white': Specified the white quarto medium
'iso-a0-white': Specifies the ISO A0 white medium
'iso-a1-white': Specifies the ISO A1 white medium
'iso-a2-white': Specifies the ISO A2 white medium
'iso-a6-white': Specifies the ISO A6 white medium
'iso-a7-white': Specifies the ISO A7 white medium
'iso-a8-white': Specifies the ISO A8 white medium
'iso-a9-white': Specifies the ISO A9 white medium
'iso-10-white': Specifies the ISO A10 white medium
'iso-b0-white': Specifies the ISO B0 white medium
'iso-b1-white': Specifies the ISO B1 white medium
'iso-b2-white': Specifies the ISO B2 white medium
'iso-b3-white': Specifies the ISO B3 white medium
'iso-b6-white': Specifies the ISO B6 white medium
'iso-b7-white': Specifies the ISO B7 white medium
'iso-b8-white': Specifies the ISO B8 white medium
'iso-b9-white': Specifies the ISO B9 white medium
'iso-b10-white': Specifies the ISO B10 white medium
'jis-b0-white': Specifies the JIS B0 white medium
'jis-b1-white': Specifies the JIS B1 white medium
'jis-b2-white': Specifies the JIS B2 white medium
'jis-b3-white': Specifies the JIS B3 white medium
'jis-b6-white': Specifies the JIS B6 white medium
'jis-b7-white': Specifies the JIS B7 white medium
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'jis-b8-white': Specifies the JIS B8 white medium
'jis-b9-white': Specifies the JIS B9 white medium
'jis-b10-white': Specifies the JIS B10 white medium
The following standard values are defined for engineering media:
'a': Specifies the engineering A size medium
'b': Specifies the engineering B size medium
'c': Specifies the engineering C size medium
'd': Specifies the engineering D size medium
'e': Specifies the engineering E size medium
The following standard values are defined for input-trays (from ISO
DPA and the Printer MIB):
'top': The top input tray in the printer.
'middle': The middle input tray in the printer.
'bottom': The bottom input tray in the printer.
'envelope': The envelope input tray in the printer.
'manual': The manual feed input tray in the printer.
'large-capacity': The large capacity input tray in the printer.
'main': The main input tray
'side': The side input tray
The following standard values are defined for media sizes (from ISO
DPA):
'iso-a0': Specifies the ISO A0 size: 841 mm by 1189 mm as defined
in ISO 216
'iso-a1': Specifies the ISO A1 size: 594 mm by 841 mm as defined in
ISO 216
'iso-a2': Specifies the ISO A2 size: 420 mm by 594 mm as defined in
ISO 216
'iso-a3': Specifies the ISO A3 size: 297 mm by 420 mm as defined in
ISO 216
'iso-a4': Specifies the ISO A4 size: 210 mm by 297 mm as defined in
ISO 216
'iso-a5': Specifies the ISO A5 size: 148 mm by 210 mm as defined in
ISO 216
'iso-a6': Specifies the ISO A6 size: 105 mm by 148 mm as defined in
ISO 216
'iso-a7': Specifies the ISO A7 size: 74 mm by 105 mm as defined in
ISO 216
'iso-a8': Specifies the ISO A8 size: 52 mm by 74 mm as defined in
ISO 216
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'iso-a9': Specifies the ISO A9 size: 37 mm by 52 mm as defined in
ISO 216
'iso-a10': Specifies the ISO A10 size: 26 mm by 37 mm as defined in
ISO 216
'iso-b0': Specifies the ISO B0 size: 1000 mm by 1414 mm as defined
in ISO 216
'iso-b1': Specifies the ISO B1 size: 707 mm by 1000 mm as defined
in ISO 216
'iso-b2': Specifies the ISO B2 size: 500 mm by 707 mm as defined in
ISO 216
'iso-b3': Specifies the ISO B3 size: 353 mm by 500 mm as defined in
ISO 216
'iso-b4': Specifies the ISO B4 size: 250 mm by 353 mm as defined in
ISO 216
'iso-b5': Specifies the ISO B5 size: 176 mm by 250 mm as defined in
ISO 216
'iso-b6': Specifies the ISO B6 size: 125 mm by 176 mm as defined in
ISO 216
'iso-b7': Specifies the ISO B7 size: 88 mm by 125 mm as defined in
ISO 216
'iso-b8': Specifies the ISO B8 size: 62 mm by 88 mm as defined in
ISO 216
'iso-b9': Specifies the ISO B9 size: 44 mm by 62 mm as defined in
ISO 216
'iso-b10': Specifies the ISO B10 size: 31 mm by 44 mm as defined in
ISO 216
'na-letter': Specifies the North American letter size: 8.5 inches by
11 inches
'na-legal': Specifies the North American legal size: 8.5 inches by
14 inches
'executive': Specifies the executive size (7.25 X 10.5 in)
'folio': Specifies the folio size (8.5 X 13 in)
'invoice': Specifies the invoice size (5.5 X 8.5 in)
'ledger': Specifies the ledger size (11 X 17 in)
'quarto': Specifies the quarto size (8.5 X 10.83 in)
'iso-c3': Specifies the ISO C3 size: 324 mm by 458 mm as defined in
ISO 269
'iso-c4': Specifies the ISO C4 size: 229 mm by 324 mm as defined in
ISO 269
'iso-c5': Specifies the ISO C5 size: 162 mm by 229 mm as defined in
ISO 269
'iso-c6': Specifies the ISO C6 size: 114 mm by 162 mm as defined in
ISO 269
'iso-designated-long': Specifies the ISO Designated Long size: 110
mm by 220 mm as defined in ISO 269
'na-10x13-envelope': Specifies the North American 10x13 size: 10
inches by 13 inches
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'na-9x12-envelope': Specifies the North American 9x12 size: 9
inches by 12 inches
'na-number-10-envelope': Specifies the North American number 10
business envelope size: 4.125 inches by 9.5 inches
'na-7x9-envelope': Specifies the North American 7x9 inch envelope
size
'na-9x11-envelope': Specifies the North American 9x11 inch envelope
size
'na-10x14-envelope': Specifies the North American 10x14 inch
envelope size
'na-number-9-envelope': Specifies the North American number 9
business envelope size
'na-6x9-envelope': Specifies the North American 6x9 envelope size
'na-10x15-envelope': Specifies the North American 10x15 envelope
size
'monarch-envelope': Specifies the Monarch envelope size (3.87 x 7.5
in)
'jis-b0': Specifies the JIS B0 size: 1030mm x 1456mm
'jis-b1': Specifies the JIS B1 size: 728mm x 1030mm
'jis-b2': Specifies the JIS B2 size: 515mm x 728mm
'jis-b3': Specifies the JIS B3 size: 364mm x 515mm
'jis-b4': Specifies the JIS B4 size: 257mm x 364mm
'jis-b5': Specifies the JIS B5 size: 182mm x 257mm
'jis-b6': Specifies the JIS B6 size: 128mm x 182mm
'jis-b7': Specifies the JIS B7 size: 91mm x 128mm
'jis-b8': Specifies the JIS B8 size: 64mm x 91mm
'jis-b9': Specifies the JIS B9 size: 45mm x 64mm
'jis-b10': Specifies the JIS B10 size: 32mm x 45mm
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15. APPENDIX D: Processing IPP Attributes
When submitting a print job to a Printer object, the IPP model allows
a client to supply operation and Job Template attributes along with
the document data. These Job Template attributes in the create
request affect the rendering, production and finishing of the
documents in the job. Similar types of instructions may also be
contained in the document to be printed, that is, embedded within the
print data itself. In addition, the Printer has a set of attributes
that describe what rendering and finishing options which are
supported by that Printer. This model, which allows for flexibility
and power, also introduces the potential that at job submission time,
these client-supplied attributes may conflict with either:
- what the implementation is capable of realizing (i.e., what the
Printer supports), as well as
- the instructions embedded within the print data itself.
The following sections describe how these two types of conflicts are
handled in the IPP model.
15.1 Fidelity
If there is a conflict between what the client requests and what a
Printer object supports, the client may request one of two possible
conflict handling mechanisms:
1) either reject the job since the job can not be processed exactly
as specified, or
2) allow the Printer to make any changes necessary to proceed with
processing the Job the best it can.
In the first case the client is indicating to the Printer object:
"Print the job exactly as specified with no exceptions, and if that
can't be done, don't even bother printing the job at all." In the
second case, the client is indicating to the Printer object: "It is
more important to make sure the job is printed rather than be
processed exactly as specified; just make sure the job is printed
even if client supplied attributes need to be changed or ignored."
The IPP model accounts for this situation by introducing an "ipp-
attribute-fidelity" attribute.
In a create request, "ipp-attribute-fidelity" is a boolean operation
attribute that is OPTIONALLY supplied by the client. The value '
true' indicates that total fidelity to client supplied Job Template
attributes and values is required. The client is requesting that the
Job be printed exactly as specified, and if that is not possible then
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the job MUST be rejected rather than processed incorrectly. The
value 'false' indicates that a reasonable attempt to print the Job is
acceptable. If a Printer does not support some of the client
supplied Job Template attributes or values, the Printer MUST ignore
them or substitute any supported value for unsupported values,
respectively. The Printer may choose to substitute the default value
associated with that attribute, or use some other supported value
that is similar to the unsupported requested value. For example, if
a client supplies a "media" value of 'na-letter', the Printer may
choose to substitute 'iso-a4' rather than a default value of '
envelope'. If the client does not supply the "ipp-attribute-fidelity"
attribute, the Printer assumes a value of 'false'.
Each Printer implementation MUST support both types of "fidelity"
printing (that is whether the client supplies a value of 'true' or '
false'):
- If the client supplies 'false' or does not supply the attribute,
the Printer object MUST always accept the request by ignoring
unsupported Job Template attributes and by substituting
unsupported values of supported Job Template attributes with
supported values.
- If the client supplies 'true', the Printer object MUST reject the
request if the client supplies unsupported Job Template
attributes.
Since a client can always query a Printer to find out exactly what is
and is not supported, "ipp-attribute-fidelity" set to 'false' is
useful when:
1) The End-User uses a command line interface to request attributes
that might not be supported.
2) In a GUI context, if the End User expects the job might be moved
to another printer and prefers a sub-optimal result to nothing
at all.
3) The End User just wants something reasonable in lieu of nothing
at all.
15.2 Page Description Language (PDL) Override
If there is a conflict between the value of an IPP Job Template
attribute and a corresponding instruction in the document data, the
value of the IPP attribute SHOULD take precedence over the document
instruction. Consider the case where a previously formatted file of
document data is sent to an IPP Printer. In this case, if the client
supplies any attributes at job submission time, the client desires
that those attributes override the embedded instructions. Consider
the case were a previously formatted document has embedded in it
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commands to load 'iso-a4' media. However, the document is passed to
an end user that only has access to a printer with 'na-letter' media
loaded. That end user most likely wants to submit that document to
an IPP Printer with the "media" Job Template attribute set to 'na-
letter'. The job submission attribute should take precedence over
the embedded PDL instruction. However, until companies that supply
document data interpreters allow a way for external IPP attributes to
take precedence over embedded job production instructions, a Printer
might not be able to support the semantics that IPP attributes
override the embedded instructions.
The IPP model accounts for this situation by introducing a "pdl-
override-supported" attribute that describes the Printer objects
capabilities to override instructions embedded in the PDL data
stream. The value of the "pdl-override-supported" attribute is
configured by means outside IPP/1.0.
This REQUIRED Printer attribute takes on the following values:
- 'attempted': This value indicates that the Printer object
attempts to make the IPP attribute values take precedence over
embedded instructions in the document data, however there is no
guarantee.
- 'not-attempted': This value indicates that the Printer object
makes no attempt to make the IPP attribute values take precedence
over embedded instructions in the document data.
At job processing time, an implementation that supports the value of
'attempted' might do one of several different actions:
1) Generate an output device specific command sequence to realize
the feature represented by the IPP attribute value.
2) Parse the document data itself and replace the conflicting
embedded instruction with a new embedded instruction that
matches the intent of the IPP attribute value.
3) Indicate to the Printer that external supplied attributes take
precedence over embedded instructions and then pass the external
IPP attribute values to the document data interpreter.
4) Anything else that allows for the semantics that IPP attributes
override embedded document data instructions.
Since 'attempted' does not offer any type of guarantee, even though a
given Printer object might not do a very "good" job of attempting to
ensure that IPP attributes take a higher precedence over instructions
embedded in the document data, it would still be a conforming
implementation.
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At job processing time, an implementation that supports the value of
'not-attempted' might do one of the following actions:
1) Simply pre-pend the document data with the PDL instruction that
corresponds to the client-supplied PDL attribute, such that if
the document data also has the same PDL instruction, it will
override what the Printer object pre-pended. In other words,
this implementation is using the same implementation semantics
for the client-supplied IPP attributes as for the Printer object
defaults.
2) Parse the document data and replace the conflicting embedded
instruction with a new embedded instruction that approximates,
but does not match, the semantic intent of the IPP attribute
value.
Note: The "ipp-attribute-fidelity" attribute applies to the
Printer's ability to either accept or reject other unsupported Job
Template attributes. In other words, if "ipp-attribute-fidelity" is
set to 'true', a Job is accepted if and only if the client supplied
Job Template attributes and values are supported by the Printer.
Whether these attributes actually affect the processing of the Job
when the document data contains embedded instructions depends on the
ability of the Printer to override the instructions embedded in the
document data with the semantics of the IPP attributes. If the
document data attributes can be overridden ("pdl-override-supported"
set to 'attempted'), the Printer makes an attempt to use the IPP
attributes when processing the Job. If the document data attributes
can not be overridden ("pdl-override-supported" set to 'not-
attempted'), the Printer makes no attempt to override the embedded
document data instructions with the IPP attributes when processing
the Job, and hence, the IPP attributes may fail to affect the Job
processing and output when the corresponding instruction is embedded
in the document data.
15.3 Using Job Template Attributes During Document Processing.
The Printer object uses some of the Job object's Job Template
attributes during the processing of the document data associated with
that job. These include, but are not limited to, "orientation",
"number-up", "sides", "media", and "copies". The processing of each
document in a Job Object MUST follow the steps below. These steps are
intended only to identify when and how attributes are to be used in
processing document data and any alternative steps that accomplishes
the same effect can be used to implement this specification.
1. Using the client supplied "document-format" attribute or some
form of document format detection algorithm (if the value of
"document- format" is not specific enough), determine whether or
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not the document data has already been formatted for printing.
If the document data has been formatted, then go to step 2.
Otherwise, the document data MUST be formatted. The formatting
detection algorithm is implementation defined and is not
specified by this specification. The formatting of the document
data uses the "orientation-requested" attribute to determine how
the formatted print data should be placed on a print-stream
page, see section 4.2.10 for the details.
2. The document data is in the form of a print-stream in a known
media type. The "page-ranges" attribute is used to select, as
specified in section 4.2.7, a sub-sequence of the pages in the
print-stream that are to be processed and images.
3. The input to this step is a sequence of print-stream pages. This
step is controlled by the "number-up" attribute. If the value of
"number-up" is N, then during the processing of the print-stream
pages, each N print-stream pages are positioned, as specified in
section 4.2.9, to create a single impression. If a given
document does not have N more print-stream pages, then the
completion of the impression is controlled by the "multiple-
document-handling" attribute as described in section 4.2.4; when
the value of this attribute is 'single-document' or 'single-
document-new-sheet', the print-stream pages of document data
from subsequent documents is used to complete the impression.
The size(scaling), position(translation) and rotation of the
print-stream pages on the impression is implementation defined.
Note that during this process the print-stream pages may be
rendered to a form suitable for placing on the impression; this
rendering is controlled by the values of the "printer-
resolution" and "print- quality" attributes as described in
sections 4.2.12 and 4.2.13. In the case N=1, the impression is
nearly the same as the print-stream page; the differences would
only be in the size, position and rotation of the print-stream
page and/or any decoration, such as a frame to the page, that is
added by the implementation.
4. The collection of impressions is placed, in sequence, onto sides
of the media sheets. This placement is controlled by the "sides"
attribute and the orientation of the print-stream page, as
described in section 4.2.8. The orientation of the print-stream
pages affects the orientation of the impression; for example, if
"number-up" equals 2, then, typically, two portrait print-stream
pages become one landscape impression. Note that the placement
of impressions onto media sheets is also controlled by the
"multiple-document-handling" attribute as described in section
4.2.4.
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5. The "copies" and "multiple-document-handling" attributes are
used to determine how many copies of each media instance are
created and in what order. See sections 4.2.5 and 4.2.4 for the
details.
6. When the correct number of copies are created, the media
instances are finished according to the values of the
"finishings" attribute as described in 4.2.6. Note that
sometimes finishing operations may require manual intervention
to perform the finishing operations on the copies, especially
uncollated copies. This specification allows any or all of the
processing steps to be performed automatically or manually at
the discretion of the Printer object.
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16. APPENDIX E: Generic Directory Schema
This section defines a generic schema for an entry in a directory
service. A directory service is a means by which service users can
locate service providers. In IPP environments, this means that IPP
Printers can be registered (either automatically or with the help of
an administrator) as entries of type printer in the directory using
an implementation specific mechanism such as entry attributes, entry
type fields, specific branches, etc. IPP clients can search or
browse for entries of type printer. Clients use the directory
service to find entries based on naming, organizational contexts, or
filtered searches on attribute values of entries. For example, a
client can find all printers in the "Local Department" context.
Authentication and authorization are also often part of a directory
service so that an administrator can place limits on end users so
that they are only allowed to find entries to which they have certain
access rights. IPP itself does not require any specific directory
service protocol or provider.
Note: Some directory implementations allow for the notion of
"aliasing". That is, one directory entry object can appear as
multiple directory entry object with different names for each object.
In each case, each alias refers to the same directory entry object
which refers to a single IPP Printer object.
The generic schema is a subset of IPP Printer Job Template and
Printer Description attributes (sections 4.2 and 4.4). These
attributes are identified as either RECOMMENDED or OPTIONAL for the
directory entry itself. This conformance labeling is NOT the same
conformance labeling applied to the attributes of IPP Printers
objects. The conformance labeling in this Appendix is intended to
apply to directory templates and to IPP Printer implementations that
subscribe by adding one or more entries to a directory. RECOMMENDED
attributes SHOULD be associated with each directory entry. OPTIONAL
attributes MAY be associated with the directory entry (if known or
supported). In addition, all directory entry attributes SHOULD
reflect the current attribute values for the corresponding Printer
object.
The names of attributes in directory schema and entries SHOULD be the
same as the IPP Printer attribute names as shown.
In order to bridge between the directory service and the IPP Printer
object, one of the RECOMMENDED directory entry attributes is the
Printer object's "printer-uri-supported" attribute. The IPP client
queries the "printer-uri-supported" attribute in the directory entry
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and then addresses the IPP Printer object using one of its URIs. The
"uri-security-supported" attribute identifies the protocol (if any)
used to secure a channel.
The following attributes define the generic schema for directory
entries of type PRINTER:
printer-uri-supported RECOMMENDED Section 4.4.1
uri-security-supported RECOMMENDED Section 4.4.2
printer-name RECOMMENDED Section 4.4.3
printer-location RECOMMENDED Section 4.4.4
printer-info OPTIONAL Section 4.4.5
printer-more-info OPTIONAL Section 4.4.6
printer-make-and-model RECOMMENDED Section 4.4.8
charset-supported OPTIONAL Section 4.4.15
generated-natural-language-
supported OPTIONAL Section 4.4.17
document-format-supported RECOMMENDED Section 4.4.19
color-supported RECOMMENDED Section 4.4.23
finishings-supported OPTIONAL Section 4.2.6
number-up-supported OPTIONAL Section 4.2.7
sides-supported RECOMMENDED Section 4.2.8
media-supported RECOMMENDED Section 4.2.11
printer-resolution-supported OPTIONAL Section 4.2.12
print-quality-supported OPTIONAL Section 4.2.13
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17. APPENDIX F: Change History for the IPP Model and Semantics document
The following substantive changes and major clarifications have been
made to this document from the June 30, 1998 version based on the
interoperability testing that took place September 23-25 1998 and
subsequent mailing list and meeting discussions. They are listed in
the order of occurrence in the document. These changes are the ones
that might affect implementations. Clarifications that are unlikely
to affect implementations are not listed. The issue numbers refer to
the IPP Issues List which is available in the following directory:
ftp://ftp.pwg.org/pub/pwg/ipp/approved-clarifications/
Section Description
global Replaced TLS references with SSL3 references as agreed with
our Area Director on 11/12/1998.
global Removed the indications that some of these IPP documents
are informational, since the intent is now to publish all
IPP/1.0 documents as informational as agreed with our Area
Director on 11/12/1998.
3.1.2, Clarify that the IPP object SHOULD NOT validate the
16.3.3 range of the request-id being 1 to 2**31-1, but accepts
[now ipp- and returns any value. Clients MUST still keep in the
iig] range 1 to 2**31 though. If the request is terminated
before the complete "request-id" is received, the IPP
object rejects the request and returns a response with a
"request-id" of 0 (Issue 1.36).
3.1.4.1, Clarified that when a client submits a request in a
13.1.4.14 charset that is not supported, the IPP object SHOULD
return any 'text' or 'name' attributes in the 'utf-8'
charset, if it returns any, since clients and IPP
objects MUST support 'utf-8'. (Issue 1.19)
3.1.4.1 Clarified Section 3.1.4.1 Request Operation Attributes
that a client MAY use the attribute level natural
language override (text/nameWithLanguage) redundantly in
a request. (Issue 1.46)
3.1.4.2 Clarified Section 3.1.4.2 Response Operation Attributes
that an IPP object MAY use the attribute level natural
language override (text/nameWithLanguage) redundantly in
a response. (Issue 1.46)
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3.1.6 Clarified section 3.1.6: If the Printer object supports
the "status-message" operation attribute, it NEED NOT
return a status message for the following error status
codes: 'client-error-bad-request', 'client-error-
charset-not-supported', 'server-error-internal-error',
'server-error-operation-not-supported', and 'server-
error-version-not-supported'.
3.2.1.1 Clarified that if a client is not supplying any Job
Template attributes in a request, the client SHOULD omit
Group 2 rather than sending an empty group. However, a
Printer object MUST be able to accept an empty group.
This makes [RFC2566] agree with [RFC2565]. (Issue 1.16)
3.2.1.2, Clarified that if an IPP object is not returning any
3.2.5.2, Unsupported Attributes in a response, the IPP object
3.2.6.2, SHOULD omit Group 2 rather than sending an empty group.
3.3.1.2, However, a client MUST be able to accept an empty group.
3.3.3.2, This makes [RFC2566] agree with [RFC2565]. (Issue 1.17)
3.3.4.2
3.2.1.2, Clarified that an IPP object MUST treat an unsupported
13.1.2.2, attribute syntax supplied in a request in the same way
13.1.4.12 as an unsupported value. The IPP object MUST return the
attribute, the attribute syntax, and the value in the
Unsupported Attributes group. (Issue 1.26)
3.2.5.2, Clarified for Get-Printer-Attributes, Get-Jobs, and Get-
3.2.6.2, Job-Attributes that an IPP object MUST return
3.3.4.2, 'successful-ok-ignored-or-substituted-attributes' (0x1),
13.1.2.1, rather than 'successful-ok' (0x0), when a client
13.1.2.2, supplies unsupported attributes as values of the
13.1.4.12 'requested-attributes' operation attribute. (Issue
1.24)
Also clarified that the response NEED NOT contain the
"requested-attributes" operation attribute with any
supplied values (attribute keywords) that were requested
by the client but are not supported by the IPP object.
(Issue 1.18)
3.2.6.2 Deleted the job-level natural language override (NLO)
4.1.1.2 from Section 3.2.6.2 Get-Jobs Response so that all
4.3.24 operation responses are the same with respect to NLO.
(Issue 1.47)
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3.3.1 Clarified that an IPP Printer that supports the Create-
Job operation MUST handle the situation when a client
does not supply Send-Document or Send-URI operations
within a one- to four-minute time period. Also
clarified that a client MUST send documents in a multi-
document job without undue or unbounded delay. (Issue
1.28)
3.3.3 Clarified that the IPP object MUST reject a Cancel-Job
request if the job is in 'completed', 'canceled', or
'aborted' job states. (Issue 1.12)
4.1.2.3 Added this new sub-section: it specifies that
nameWithoutLanguage plus the implicit natural language
matches nameWithLanguage, if the values and natural
languages are the same. Also added that keyword never
matches nameWithLanguage or nameWithoutLanguage.
Clarified that if both have countries, that the
countries SHOULD match as well. If either do not, then
the country field SHOULD be ignored. (Issues 1.33 and
1.34)
4.1.5 Clarified regarding the case-insensitivity of URLs to
refer only to the RFCs that define them. (Issue 1.10)
4.1.11 Clarified that 'boolean' is not a full-sized integer.
(Issue 1.38)
4.1.15 Clarified that 'resolution' is not three full-sized
integers. (Issue 1.20)
4.2.* Clarified that standard values are keywords or enums,
not names. (Issue 1.49).
4.2.4 Added the 'single-document-new-sheet' value to Section
4.2.4 multiple-document-handling. (Issue 1.54)
4.4.18, Clarified that the "document-format-default" and
4.4.19 "document-format-supported" Printer Description
attributes are REQUIRED to agree with the table. (Issue
1.4)
4.4.21 Changed "queued-job-count" from OPTIONAL to RECOMMENDED.
(Issue 1.14)
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4.4.28 Clarified that the implementation supplied value for the
"multiple-operation-time-out" attribute SHOULD be
between 30 and 240 seconds, though the implementation
MAY allow the administrator to set values, and MAY allow
values outside this range. (Issue 1.28)
5.1, Clarified Client Conformance that if a client supports
5.2.5 an attribute of 'text' attribute syntax, that it MUST
support both the textWithoutLanguage and the
textWithLanguage forms. Same for 'name' attribute
syntax. Same for an IPP object (Issue 1.48)
6.5, Added new section to allow Attribute Groups to be
12.8 registered as extensions for being passed in operation
requests and responses. (Issue 1.25)
7. Updated the table of text and name attributes to agree
with Section 4.2.
8.5 Added a new section RECOMMENDING that the Get-Jobs
SHOULD return non-IPP jobs whether or not assigning them
a job-id and job-uri. Also RECOMMENDED generating, if
possible, job-id and job-uri and supporting other IPP
operations on foreign jobs as an implementer option.
(Issue 1.32)
9. Updated document references.
13.1.4.14 Clarified 'client-error-charset-not-supported' that
'utf-8' must be used for any 'text' or 'name' attributes
returned in the error response (Issue 1.19).
13.1.5.9 Added a new error code 'server-error-job-canceled'
(0x0508) to be returned if a job is canceled by another
client or aborted by the IPP object while the first
client is still sending the document data. (Issue 1.29)
15.3, Moved these sections recommending operation processing
15.4 steps to the new Implementer's Guide (informational).
There indicated that all of the error checks are not
required, so an IPP object MAY be forgiving and accept
non-conforming requests. However, a conforming client
MUST supply requests that would pass all of the error
checks indicated. (Issue 1.21)
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16 Changed directory schema attributes from REQUIRED to
RECOMMENDED. Changed some of the OPTIONAL to
RECOMMENDED to agree with the SLP template. Changed the
"charset-supported" and "natural-language-supported"
from REQUIRED to OPTIONAL. Recommended that the names
be the same in a directory entry as the IPP attribute
names. (Issue 1.53)
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18. Full Copyright Statement
Copyright (C) The Internet Society (1999). All Rights Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
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