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Independent Submission M. Stubbig
Request for Comments: 8522 Independent
Category: Informational February 2019
ISSN: 2070-1721
Looking Glass Command Set
Abstract
This document introduces a command set standard to the web-based
"Network Looking Glass" software. Its purpose is to provide
application programmers uniform access to the Looking Glass service
and to analyze a standardized response.
The interface is supposed to provide the same level of information as
web-based interfaces, but in a computer-readable format.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This is a contribution to the RFC Series, independently of any other
RFC stream. The RFC Editor has chosen to publish this document at
its discretion and makes no statement about its value for
implementation or deployment. Documents approved for publication by
the RFC Editor are not candidates for any level of Internet Standard;
see Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8522.
Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Background . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Syntax Notation . . . . . . . . . . . . . . . . . . . . . 3
1.3. Examples . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Method Parameters . . . . . . . . . . . . . . . . . . . . 4
2.2. Query Parameters . . . . . . . . . . . . . . . . . . . . 5
2.3. Response . . . . . . . . . . . . . . . . . . . . . . . . 6
3. Functions . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.1. Diagnostic Commands . . . . . . . . . . . . . . . . . . . 9
3.2. Informational Commands . . . . . . . . . . . . . . . . . 10
3.3. Organizational Commands . . . . . . . . . . . . . . . . . 14
3.4. Extensible Commands . . . . . . . . . . . . . . . . . . . 16
4. Miscellaneous . . . . . . . . . . . . . . . . . . . . . . . . 16
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
5.1. Well-Known URIs Registry . . . . . . . . . . . . . . . . 17
6. Security Considerations . . . . . . . . . . . . . . . . . . . 17
6.1. Abuse Potential . . . . . . . . . . . . . . . . . . . . . 17
6.2. Authentication . . . . . . . . . . . . . . . . . . . . . 17
6.3. Minimal Information . . . . . . . . . . . . . . . . . . . 17
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 18
7.1. Normative References . . . . . . . . . . . . . . . . . . 18
7.2. Informative References . . . . . . . . . . . . . . . . . 19
Appendix A. JSend . . . . . . . . . . . . . . . . . . . . . . . 20
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 20
1. Introduction
Many Internet service providers (ISPs) and Internet exchange points
(IXPs) offer a complimentary web-based service to their customers and
the general public that gives insights to the backbone routing table,
BGP neighbor information, or offered routes. This service is known
as a "Network Looking Glass". Because they utilize a web-based
interface, it is hard to automate access to the services and make
that automation transferable between different service
implementations.
This document describes a common command set to provide application
programmers uniform access to Looking Glass services.
The commands are intended to provide the same level of information as
available via web-based interfaces, but to do so in a computer-
readable format. The intention is that multiple implementers of
Looking Glass services can provide access through these commands so
that an application can make use of the different implementations.
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The command set is split into the following categories: mandatory to
support, optional, and additional. The commands are extensible for
new features and for value-add by implementations.
The Looking Glass command set is described as a language-independent
concept. Consequently, any programming language that satisfies the
commands listed in the following sections is acceptable.
This work is not the output of the IETF and is presented in the hope
that Looking Glass implementers will offer a common programmable
interface.
1.1. Background
The requirement of a uniform access to a Looking Glass service
becomes important when multiple Looking Glasses are part of a
monitoring system. Implementing a web client and HTTP parser for
every kind of web-based Looking Glass is a time-consuming workaround.
However, the Looking Glass command set is a much more viable,
compatible, and scalable solution.
1.2. Syntax Notation
This specification uses the JavaScript Object Notation (JSON) of
[RFC8259] arranged as JSend-compliant (Appendix A) responses.
1.3. Examples
All URLs in this documentation use the reserved sample domain of
"example.net" as defined in Section 6.5 of [RFC6761].
The URLs further use the fixed [RFC5785] prefix of ".well-known/
looking-glass" to prevent a collision in the domain's namespace.
IPv4 addresses use the documentation block of 192.0.2.0/24 [RFC5737]
and IPv6 addresses reside in the reserved prefix of 2001:DB8::/32
[RFC3849]. BGP Autonomous System (AS) numbers are chosen from the
private AS range defined in [RFC6996].
The examples skip some required parameters for reasons of simplicity.
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2. Operation
A client issues a query using the HTTP GET method to request specific
resources from the server. The resource is a URI and can be
informational or a command execution. The client must present all
necessary parameters for the server to execute the command on the
selected router. Every call is stateless and independent of the
previous one.
The path component of the resource URI must use the prefix of ".well-
known/looking-glass" (see Section 5.1) to stay namespace neutral.
The "call" is a request from the client that specifies a predefined
operation ("function") that the server will execute on a selected
router. The "command" is a task executed on the router and initiated
by the server on behalf of the client. The type and scope of all
commands are defined and limited by the server. The client must not
be able to execute random commands on the targeting router. There
must not be any direct communication between the client and the
router.
After the execution of the command on the selected router has
finished, the server replies to the client if the operation has
either succeeded, failed, or timed out. The response is sent to the
client in JSON format. The communication protocol used between the
server and router is not specified by this document; any method
(e.g., Telnet, SSH, NETCONF, serial console) is acceptable.
All parameters and their values are case insensitive.
2.1. Method Parameters
Method parameters are mandatory components of the URI and are placed
in the "path" section in terms of [RFC7320]. Basically, the method
parameters specify the call and determine which command the client
wants to be executed on the selected router.
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2.2. Query Parameters
Query parameters are optional components of the URI and are placed in
the "query" section in terms of [RFC7320]. Generally, the query
parameters are additional instructions for the requested command.
protocol
Restrict the command and method parameters to use the specified
protocol and version. Protocol is selected as "Address Family
Identifier" [IANA-AFN] [RFC4760] and optionally as "Subsequent
Address Family Identifier" [IANA-SAFI] separated by a comma.
Default value is 1,1 (IP version 4, unicast).
JSON datatype is String.
Examples:
* protocol=2,1 (IP version 6, unicast)
* protocol=26 (MPLS, no SAFI used)
router
Run the command on the router identified by its name. This is not
necessarily the router's hostname as long as the Looking Glass
software recognizes it.
Default value is the first router in the list of available
routers.
JSON datatype is String.
Example: router=rbgn06.example.net
routerindex
Run the command on this router identified by its position in the
list of available routers.
Default value is "0".
JSON datatype is Number.
Example: routerindex=8
random
Append a random string to prevent the client (or an intermediate
proxy) from caching the response. The server must ignore its
value.
No default value.
JSON datatype is String.
Example: random=517A93B50
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vrf
Run the command from the selected routing table. This parameter
is valid only on routers that support "Virtual Routing and
Forwarding" (VRF).
No default value.
JSON datatype is String.
Example: vrf=mgmt
runtime
Stop executing the command after the runtime limit (in seconds) is
exceeded. A value of 0 disables the limit.
Default value is "30".
JSON datatype is Number.
Example: runtime=60
format
Request the server to provide the output (if any) in the selected
format. Specify multiple formats separated by a comma in
descending order of preference. See Section 3.3.2 for more
details.
Default value is "text/plain" (raw/unformatted output).
JSON datatype is String.
Example: format=application/yang,text/plain
2.3. Response
The HTTP response header contains an appropriate HTTP status code as
defined in [RFC7231] with the Content-Type set to "application/json".
The HTTP body contains details and error descriptions. The response
text must comply with the JSON syntax specification JSend, which is
briefly explained in Appendix A. Consequently, every response must
contain a "status" field of either "success", "fail", or "error" as
explained in the following sections.
2.3.1. Success
A successful response must set the "status" field to "success". It
must also contain a "data" object including the following
information:
performed_at
Combined date and time in UTC ISO 8601 [iso8601] indicating when
the operation finished. This information must be present.
runtime
Amount of seconds (wallclock) used to run the command. This
information must be present.
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router
Name of the router that executed the command. This information
may be present.
output
Output of the command in a format that was requested by the
client; it otherwise defaults to raw output as it appeared on the
router's command-line interface (CLI). It might even be blank if
the command did not produce any output. This information should
be present.
format
Selected output format by the server. The client might request
multiple formats so that the "Looking Glass" server has to choose
the best option and tell the client which format was selected.
This information should be present (defaults to "text/plain" if
missing).
Adding more information to the response is permitted and must be
placed inside the "data" object.
The HTTP status code should be 200.
Example:
HTTP/1.1 200 OK
Content-Type: application/json
{
"status" : "success",
"data" : {
"router" : "route-server.lookingglass.example.net"
"performed_at" : "2014-10-15T17:15:34Z",
"runtime" : 2.63,
"output" : [
"full raw output from the observing router..."
],
"format" : "text/plain"
}
}
2.3.2. Fail
A status of "fail" indicates that the selected command was executed
on the router but failed to succeed. The response message must set
the "status" field to "fail" and must contain the "data" object with
command-specific content listed in Section 2.3.1.
The HTTP status code should be 200.
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Example:
HTTP/2.0 200 OK
{
"status" : "fail",
"data" : {
"performed_at" : "2014-10-18T20:04:37Z",
"runtime" : 10.37,
"output" : [
"Sending 5, 100-byte ICMP Echos to 192.0.2.5",
".....",
"Success rate is 0 percent (0/5)"
],
"format" : "text/plain",
"router" : "route-server.lookingglass.example.net"
}
}
2.3.3. Error
The status "error" represents either that the command timed out or
that an error occurred in processing the request. The response
message must set the "status" field to "error" and must contain the
"message" key, which keeps a meaningful message, explaining what went
wrong.
The response may contain the "data" key with required values listed
in Section 2.3.1. It may also include a "code" field that carries a
numeric code corresponding to the error.
The HTTP status code should be 400 in case of a client-side error,
500 in case of a server-side error, or 502 for errors occurring on
the target router. Code 504 should be used when a command timed out.
Example:
HTTP/1.1 400 Bad Request
{
"status" : "error",
"message" : "Unrecognized host or address."
}
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3. Functions
The Looking Glass command set provides functions that are either
mandatory to support or optional to implement. The same principle
applies to the web-based Looking Glass.
It is not possible for any function to modify the server's state.
Therefore, all HTTP methods are GET operations.
Variables are templated and expanded in accordance with [RFC6570].
3.1. Diagnostic Commands
3.1.1. Ping
Send echo messages to validate the reachability of a remote host and
measure round-trip time. The host can be a name or address.
Implementation of the ping command is mandatory.
Syntax: https://example.net/.well-known/looking-glass/v1/ping/{host}
Example query:
GET /.well-known/looking-glass/v1/ping/2001:DB8::35?protocol=2,1
Host: example.net
Example response:
HTTP/1.1 200 OK
{
"status" : "success",
"data" : {
"min" : 40,
"avg" : 41,
"max" : 44,
"rate" : 100,
"output" : [
"Sending 5, 100-byte ICMP Echos to 2001:DB8::35",
"!!!!!",
"Success rate is 100 percent (5/5)"
],
"format" : "text/plain",
"performed_at" : "2014-10-04T14:40:58Z",
"runtime" : 0.77,
"router" : "c2951.lab.lg.example.net"
}
}
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3.1.2. Traceroute
Trace the path from the executing router to the destination host and
list all intermediate hops. The host can be a name or address.
Implementation of the traceroute command is optional.
Syntax: https://example.net/.well-known/looking-glass/v1/
traceroute/{host}
Example query:
GET /.well-known/looking-glass/v1/traceroute/192.0.2.8?routerindex=5
Host: example.net
Example response:
HTTP/1.1 200 OK
{
"status": "success",
"data": {
"output": [
"Tracing the route to 192.0.2.8",
"",
" 1 198.51.100.77 28 msec 28 msec 20 msec",
" 2 203.0.113.130 52 msec 40 msec 40 msec",
" 3 192.0.2.8 72 msec 76 msec 68 msec"
],
"format": "text/plain",
"performed_at": "2018-06-10T12:09:31Z",
"runtime": 4.21,
"router": "c7206.lab.lg.example.net"
}
}
3.2. Informational Commands
3.2.1. show route
Retrieve information about a specific subnet from the routing table.
Implementation of the "show route" command is mandatory.
Syntax: https://example.net/.well-known/looking-glass/v1/show/
route/{addr}
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Example query:
GET /.well-known/looking-glass/v1/show/ [multiline]
route/2001:DB8::/48?protocol=2,1
Host: example.net
Example response:
HTTP/1.1 200 OK
{
"status": "success",
"data": {
"output": [
"S 2001:DB8::/48 [1/0]",
" via FE80::C007:CFF:FED9:17, FastEthernet0/0"
],
"format": "text/plain",
"performed_at": "2018-06-11T17:13:39Z",
"runtime": 1.39,
"router": "c2951.lab.lg.example.net"
}
}
3.2.2. show bgp
Display a matching record from the BGP routing table. This should
include networks, next hop, and may include metric, local preference,
path list, weight, etc.
Implementation of the "show bgp" command is optional.
Syntax: https://example.net/.well-known/looking-glass/v1/show/
bgp/{addr}
Example query:
GET /.well-known/looking-glass/v1/show/bgp/192.0.2.0/24
Host: example.net
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Example response:
HTTP/1.1 200 OK
{
"status": "success",
"data": {
"output": [
"BGP routing table entry for 192.0.2.0/24, version 2",
"Paths: (2 available, best #2, table default)",
" Advertised to update-groups:",
" 1",
" Refresh Epoch 1",
" Local",
" 192.0.2.226 from 192.0.2.226 (192.0.2.226)",
" Origin IGP, metric 0, localpref 100, valid, internal",
"[...]"
],
"format": "text/plain",
"performed_at": "2018-06-11T21:47:17Z",
"runtime": 2.03,
"router": "c2951.lab.lg.example.net"
}
}
3.2.3. show bgp summary
Print a summary of BGP neighbor status. This may include the
neighbor BGP ID, autonomous system number, duration of peering,
number of received prefixes, etc.
Implementation of the "show bgp summary" command is optional.
Syntax: https://example.net/.well-known/looking-glass/v1/show/bgp/
summary
Example:
GET /.well-known/looking-glass/v1/show/bgp/summary? [multiline]
protocol=2&routerindex=3
Host: example.net
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Example response:
HTTP/1.1 200 OK
{
"status": "success",
"data": {
"output": [
"BGP router identifier 192.0.2.18, local AS number 64501",
"BGP table version is 85298, main routing table version 85298",
"50440 network entries using 867568 bytes of memory",
"[...]",
"Neighbor V AS MsgRcvd MsgSent TblVer Up/Down",
"2001:DB8:91::24 4 64500 481098 919095 85298 41w5d"
],
"format": "text/plain",
"performed_at": "2018-06-11T21:59:21Z",
"runtime": 1.91,
"router": "c2951.lab.lg.example.net"
}
}
3.2.4. show bgp neighbors
Provide detailed information on BGP neighbor connections. Available
details may include neighbor BGP ID, advertised networks, learned
networks, autonomous system number, capabilities, protocol,
statistics, etc.
Implementation of the "show bgp neighbors" command is optional.
Syntax: https://example.net/.well-known/looking-glass/v1/show/bgp/
neighbors/{addr}
Example query:
GET /.well-known/looking-glass/v1/show/bgp/neighbors/192.0.2.226
Host: example.net
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Example response:
HTTP/1.1 200 OK
{
"status": "success",
"data": {
"output": [
"BGP neighbor is 192.0.2.226, remote AS 64500, internal link",
" BGP version 4, remote router ID 198.51.100.31",
" BGP state = Established, up for 01:24:06",
"[...]"
],
"format": "text/plain",
"performed_at": "2018-06-11T21:41:17Z",
"runtime": 1.87,
"router": "c2951.lab.lg.example.net"
}
}
3.3. Organizational Commands
The following organizational commands must be included in the
implementation.
3.3.1. router list
Provides a full list of routers that are available for command
execution. This list includes the router ID and its name. It is
equivalent to the common "router" HTML drop-down form element and
contains the same information.
Syntax: https://example.net/.well-known/looking-glass/v1/routers
Example response:
{
"status" : "success",
"data" : {
"routers" : [
"route-server.lookingglass.example.net",
"customer-edge.lookingglass.example.net",
"provider-edge.lookingglass.example.net"
],
"performed_at" : "2014-10-19T20:07:01Z",
"runtime" : 0.73
}
}
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3.3.2. router details
Lists additional information about the selected router specified by
its router index. The response must contain the router's hostname
and router index. The response may contain more details like output
format, country code, city, administrative contact, vendor, and
model.
Available output formats are specified by Internet media type as of
[RFC6838] and listed in [IANA-MT]. If the routers support multiple
formats, they are separated by a comma.
The router might provide output formats that are not yet registered
or listed in [IANA-MT]. For example, output in NETCONF format could
use "text/x.netconf". [RFC6838] provides a tree for unregistered
subtypes.
A missing output format defaults to "text/plain", which is a copy of
the raw command-line output.
Syntax: https://example.net/.well-known/looking-glass/v1/
routers/{number}
Example query:
GET /.well-known/looking-glass/v1/routers/1
Host: example.net
Example response:
{
"status" : "success",
"data" : {
"id" : 1,
"name" : "customer-edge.lookingglass.example.net",
"format" : "text/plain,text/x.netconf",
"country" : "de",
"autonomous_system" : 64512
}
}
3.3.3. commands
Provides a full list of commands that are available for execution.
The list includes mandatory to support, optional, and additional
(Section 3.4) commands. It is equivalent to the "command" HTML drop-
down or radio-button form element and contains the same information.
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The list is formatted as a "commands" array containing one object per
command. This object contains informative strings about the current
command: href, arguments, description, and command.
Syntax: https://example.net/.well-known/looking-glass/v1/cmd
Example response:
{
"status" : "success",
"data" : {
"commands" : [
{
"href" : "https://example.net/.well-known/ [multiline]
looking-glass/v1/show/route",
"arguments" : "{addr}",
"description" : "Print records from IP routing table",
"command" : "show route"
},
{
"href" : "https://example.net/.well-known/ [multiline]
looking-glass/v1/traceroute",
"arguments" : "{addr}",
"description" : "Trace route to destination host",
"command" : "traceroute"
}
]
}
}
3.4. Extensible Commands
The list of commands discussed in Section 3.3.3 may be expanded as
long as the principles of this document are observed.
For example, a Looking Glass provider may not be offering BGP-related
commands because of an OSPF-based network.
The sample command might be:
GET /.well-known/looking-glass/v1/show/ospf/database
Host: example.net
4. Miscellaneous
The network traffic sent by a "Looking Glass" is not appropriate when
measuring Service Level Agreements or validating Quality of Service
settings.
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If a monitoring system uses the Looking Glass command set for
reachability checks, it should not rely on the HTTP status codes but
on the "status" message field inside the HTTP body.
5. IANA Considerations
5.1. Well-Known URIs Registry
This specification registers a Well-Known URI [RFC5785]:
URI Suffix: looking-glass
Change Controller: M. Stubbig
Reference : This document, Section 2
6. Security Considerations
The use of HTTPS is required to ensure a high level of security,
privacy, and confidentiality during transit.
6.1. Abuse Potential
The main goal of the Looking Glass command set is the automated usage
of the Looking Glass service. This allows the scripting of API
calls, which could be used as a Distributed Denial of Service (DDoS)
attack. It is recommended that implementers of the Looking Glass API
take steps to mitigate the above described abuse. The strategy can
include blocking or rate-limiting by client IP address or target IP
network.
6.2. Authentication
Authentication is not a requirement because the current Looking Glass
web services are usable without authentication. Requests to the
proposed API service may be authenticated by any method. The
decision is up to the implementer's security requirements.
6.3. Minimal Information
Some of the described commands provide a detailed insight into the
provider's network. It is therefore up to the implementer's security
policy to dismiss commands that are marked as "optional" or to
restrict commands that are marked as "mandatory".
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7. References
7.1. Normative References
[IANA-AFN] IANA, "Address Family Numbers", <https://www.iana.org/
assignments/address-family-numbers/>.
[IANA-MT] IANA, "Media Types",
<https://www.iana.org/assignments/media-types/>.
[IANA-SAFI]
IANA, "Subsequent Address Family Identifiers (SAFI)
Parameters",
<https://www.iana.org/assignments/safi-namespace/>.
[JSend] OmniTI Labs, "JSend", 2014,
<https://labs.omniti.com/labs/jsend>.
[RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
"Multiprotocol Extensions for BGP-4", RFC 4760,
DOI 10.17487/RFC4760, January 2007,
<https://www.rfc-editor.org/info/rfc4760>.
[RFC5785] Nottingham, M. and E. Hammer-Lahav, "Defining Well-Known
Uniform Resource Identifiers (URIs)", RFC 5785,
DOI 10.17487/RFC5785, April 2010,
<https://www.rfc-editor.org/info/rfc5785>.
[RFC6570] Gregorio, J., Fielding, R., Hadley, M., Nottingham, M.,
and D. Orchard, "URI Template", RFC 6570,
DOI 10.17487/RFC6570, March 2012,
<https://www.rfc-editor.org/info/rfc6570>.
[RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
DOI 10.17487/RFC7231, June 2014,
<https://www.rfc-editor.org/info/rfc7231>.
[RFC8259] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", STD 90, RFC 8259,
DOI 10.17487/RFC8259, December 2017,
<https://www.rfc-editor.org/info/rfc8259>.
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RFC 8522 Looking Glass Command Set February 2019
7.2. Informative References
[iso8601] International Organization for Standardization, "Data
elements and interchange formats - Information interchange
- Representation of dates and times", December 2004.
[RFC3849] Huston, G., Lord, A., and P. Smith, "IPv6 Address Prefix
Reserved for Documentation", RFC 3849,
DOI 10.17487/RFC3849, July 2004,
<https://www.rfc-editor.org/info/rfc3849>.
[RFC5737] Arkko, J., Cotton, M., and L. Vegoda, "IPv4 Address Blocks
Reserved for Documentation", RFC 5737,
DOI 10.17487/RFC5737, January 2010,
<https://www.rfc-editor.org/info/rfc5737>.
[RFC6761] Cheshire, S. and M. Krochmal, "Special-Use Domain Names",
RFC 6761, DOI 10.17487/RFC6761, February 2013,
<https://www.rfc-editor.org/info/rfc6761>.
[RFC6838] Freed, N., Klensin, J., and T. Hansen, "Media Type
Specifications and Registration Procedures", BCP 13,
RFC 6838, DOI 10.17487/RFC6838, January 2013,
<https://www.rfc-editor.org/info/rfc6838>.
[RFC6996] Mitchell, J., "Autonomous System (AS) Reservation for
Private Use", BCP 6, RFC 6996, DOI 10.17487/RFC6996, July
2013, <https://www.rfc-editor.org/info/rfc6996>.
[RFC7320] Nottingham, M., "URI Design and Ownership", BCP 190,
RFC 7320, DOI 10.17487/RFC7320, July 2014,
<https://www.rfc-editor.org/info/rfc7320>.
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Appendix A. JSend
According to [JSend]:
JSend is a specification that lays down some rules for how JSON
responses from web servers should be formatted. JSend focuses on
application-level (as opposed to protocol- or transport-level)
messaging which makes it ideal for use in REST-style applications
and APIs.
A basic JSend-compliant response must contain a "status" key and
should contain "data", "message", and "code" keys dependent on the
status value. The following table lists the required and optional
keys.
+---------+-----------------+---------------+
| Type | Required keys | Optional keys |
+---------+-----------------+---------------+
| success | status, data | |
| fail | status, data | |
| error | status, message | code, data |
+---------+-----------------+---------------+
Table 1: Type and Keys in JSend Response
Author's Address
Markus Stubbig
Independent
Germany
Email: stubbig.ietf@gmail.com
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