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Internet Engineering Task Force (IETF) E. Bellagamba
Request for Comments: 7759
Category: Standards Track G. Mirsky
ISSN: 2070-1721 Ericsson
L. Andersson
Huawei Technologies
P. Skoldstrom
Acreo AB
D. Ward
Cisco
J. Drake
Juniper
February 2016
Configuration of Proactive Operations,
Administration, and Maintenance (OAM) Functions for MPLS-Based
Transport Networks Using Label Switched Path (LSP) Ping
Abstract
This specification describes the configuration of proactive MPLS-TP
Operations, Administration, and Maintenance (OAM) functions for a
given Label Switched Path (LSP) using a set of TLVs that are carried
by the LSP Ping protocol.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7759.
Bellagamba, et al. Standards Track [Page 1]
RFC 7759 Extensions for MPLS-TP OAM Config. February 2016
Copyright Notice
Copyright (c) 2016 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
(http://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. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction ....................................................3
1.1. Conventions Used in This Document ..........................4
1.1.1. Terminology .........................................4
1.1.2. Requirements Language ...............................5
2. Theory of Operations ............................................5
2.1. MPLS OAM Configuration Operation Overview ..................5
2.1.1. Configuration of BFD Sessions .......................5
2.1.2. Configuration of Performance Monitoring .............6
2.1.3. Configuration of Fault Management Signals ...........6
2.2. MPLS OAM Functions TLV .....................................7
2.2.1. BFD Configuration Sub-TLV ...........................9
2.2.2. BFD Local Discriminator Sub-TLV ....................11
2.2.3. BFD Negotiation Timer Parameters Sub-TLV ...........11
2.2.4. BFD Authentication Sub-TLV .........................13
2.2.5. Traffic Class Sub-TLV ..............................14
2.2.6. Performance Monitoring Sub-TLV .....................14
2.2.7. PM Loss Measurement Sub-TLV ........................17
2.2.8. PM Delay Measurement Sub-TLV .......................18
2.2.9. Fault Management Signal Sub-TLV ....................20
2.2.10. Source MEP-ID Sub-TLV .............................21
3. Summary of MPLS OAM Configuration Errors .......................22
4. IANA Considerations ............................................23
4.1. TLV and Sub-TLV Allocation ................................23
4.2. MPLS OAM Function Flags Allocation ........................24
4.3. OAM Configuration Errors ..................................25
5. Security Considerations ........................................26
6. References .....................................................26
6.1. Normative References ......................................26
6.2. Informative References ....................................27
Acknowledgements .................................................28
Authors' Addresses ................................................29
Bellagamba, et al. Standards Track [Page 2]
RFC 7759 Extensions for MPLS-TP OAM Config. February 2016
1. Introduction
The MPLS Transport Profile (MPLS-TP) describes a profile of MPLS that
enables operational models typical in transport networks while
providing additional Operations, Administration, and Maintenance
(OAM), survivability, and other maintenance functions not currently
supported by MPLS. [RFC5860] defines the requirements for the OAM
functionality of MPLS-TP.
This document describes the configuration of proactive MPLS-TP OAM
functions for a given Label Switched Path (LSP) using TLVs carried in
LSP Ping [RFC4379]. In particular, it specifies the mechanisms
necessary to establish MPLS-TP OAM entities at the maintenance points
for monitoring and performing measurements on an LSP, as well as
defining information elements and procedures to configure proactive
MPLS-TP OAM functions running between Label Edge Routers (LERs).
Initialization and control of on-demand MPLS-TP OAM functions are
expected to be carried out by directly accessing network nodes via a
management interface; hence, configuration and control of on-demand
OAM functions are out of scope for this document.
The Transport Profile of MPLS must, by definition [RFC5654], be
capable of operating without a control plane. Therefore, there are a
few options for configuring MPLS-TP OAM: without a control plane
using a Network Management System (NMS), implementing LSP Ping
instead or with a control plane implementing extensions to signaling
protocols RSVP Traffic Engineering (RSVP-TE) [RFC3209] and/or
Targeted LDP [RFC5036].
Proactive MPLS-TP OAM is performed by a set of protocols:
Bidirectional Forwarding Detection (BFD) [RFC6428] for Continuity
Check/Connectivity Verification, the Delay Measurement (DM) protocol
[RFC6374], [RFC6375] for delay and delay variation (jitter)
measurements, and the Loss Measurement (LM) protocol [RFC6374],
[RFC6375] for packet loss and throughput measurements. Additionally,
there are a number of Fault Management Signals that can be configured
[RFC6427].
BFD is a protocol that provides low-overhead, fast detection of
failures in the path between two forwarding engines, including the
interfaces, data link(s), and to the extent possible, the forwarding
engines themselves. BFD can be used to detect the continuity and
mis-connection defects of MPLS-TP point-to-point and might also be
extended to support point-to-multipoint LSPs.
The delay and loss measurements protocols [RFC6374] and [RFC6375] use
a simple query/response model for performing both unidirectional and
bidirectional measurements that allow the originating node to measure
Bellagamba, et al. Standards Track [Page 3]
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packet loss and delay in forward, or forward and reverse directions.
By timestamping and/or writing current packet counters to the
measurement packets (four times, Transmit and Receive in both
directions), current delays and packet losses can be calculated. By
performing successive delay measurements, the delay and/or inter-
packet delay variation (jitter) can be calculated. Current
throughput can be calculated from the packet loss measurements by
dividing the number of packets sent/received with the time it took to
perform the measurement, given by the timestamp in the LM header.
Combined with a packet generator, the throughput measurement can be
used to measure the maximum capacity of a particular LSP. It should
be noted that this document does not specify how to configure
on-demand throughput estimates based on saturating the connection as
defined in [RFC6371]; rather, it only specifies how to enable the
estimation of the current throughput based on loss measurements.
1.1. Conventions Used in This Document
1.1.1. Terminology
BFD - Bidirectional Forwarding Detection
DM - Delay Measurement
FMS - Fault Management Signal
G-ACh - Generic Associated Channel
LSP - Label Switched Path
LM - Loss Measurement
MEP - Maintenance Entity Group End Point
MPLS - Multi-Protocol Label Switching
MPLS-TP - MPLS Transport Profile
NMS - Network Management System
PM - Performance Monitoring
RSVP-TE - RSVP Traffic Engineering
TC - Traffic Class
Bellagamba, et al. Standards Track [Page 4]
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1.1.2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
2. Theory of Operations
2.1. MPLS OAM Configuration Operation Overview
The MPLS-TP OAM tool set is described in [RFC6669].
LSP Ping, or alternatively RSVP-TE [RFC7487], can be used to easily
enable the different OAM functions by setting the corresponding flags
in the MPLS OAM Functions TLV (refer to Section 2.2). For a more
detailed configuration, one may include sub-TLVs for the different
OAM functions in order to specify various parameters in detail.
Typically, intermediate nodes simply forward OAM configuration TLVs
to the end node without any processing or modification. At least one
exception to this is if the FMS sub-TLV (refer to Section 2.2.9 ) is
present. This sub-TLV MUST be examined even by intermediate nodes
that support this extension. The sub-TLV MAY be present if a flag is
set in the MPLS OAM Functions TLV.
2.1.1. Configuration of BFD Sessions
For this specification, BFD MUST run in either one of the two modes:
o Asynchronous mode, where both sides are in active mode
o Unidirectional mode
In the simplest scenario, LSP Ping [RFC5884], or alternatively RSVP-
TE [RFC7487], is used only to bootstrap a BFD session for an LSP,
without any timer negotiation.
Timer negotiation can be performed either in subsequent BFD control
messages (in this case the operation is similar to bootstrapping
based on LSP Ping described in [RFC5884]), or directly in the LSP
Ping configuration messages.
When BFD Control packets are transported in the Associated Channel
Header (ACH) encapsulation, they are not protected by any end-to-end
checksum; only lower layers provide error detection/correction. A
single bit error, e.g., a flipped bit in the BFD State field, could
cause the receiving end to wrongly conclude that the link is down and
in turn trigger protection switching. To prevent this from
Bellagamba, et al. Standards Track [Page 5]
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happening, the BFD Configuration sub-TLV (refer to Section 2.2.1) has
an Integrity flag that, when set, enables BFD Authentication using
Keyed SHA1 with an empty key (all 0s) [RFC5880]. This would make
every BFD Control packet carry a SHA1 hash of itself that can be used
to detect errors.
If BFD Authentication using a pre-shared key/password is desired
(i.e., authentication and not only error detection), the BFD
Authentication sub-TLV (refer to Section 2.2.4) MUST be included in
the BFD Configuration sub-TLV. The BFD Authentication sub-TLV is
used to specify which authentication method that should be used and
which pre-shared key/password that should be used for this particular
session. How the key exchange is performed is out of scope of this
document.
2.1.2. Configuration of Performance Monitoring
It is possible to configure Performance Monitoring functionalities
such as Loss, Delay, Delay/Interpacket Delay variation (jitter), and
throughput as described in [RFC6374].
When configuring Performance Monitoring functionalities, it is
possible to choose either the default configuration, by only setting
the respective flags in the MPLS OAM functions TLV, or a customized
configuration. To customize the configuration, one would set the
respective flags in the MPLS OAM functions TLV and include the
respective Loss and/or Delay sub-TLVs.
By setting the PM Loss flag in the MPLS OAM Functions TLV and
including the PM Loss sub-TLV (refer to Section 2.2.7), one can
configure the measurement interval and loss threshold values for
triggering protection.
Delay measurements are configured by setting the PM Delay flag in the
MPLS OAM Functions TLV and by including the PM Delay sub-TLV (refer
to Section 2.2.8), one can configure the measurement interval and the
delay threshold values for triggering protection.
2.1.3. Configuration of Fault Management Signals
To configure Fault Management Signals (FMSs) and their refresh time,
the FMS Flag in the MPLS OAM Functions TLV MUST be set and the FMS
sub-TLV MUST be included. When configuring an FMS, an implementation
can enable the default configuration by setting the FMS Flag in the
OAM Function Flags sub-TLV. In order to modify the default
configuration, the MPLS OAM FMS sub-TLV MUST be included.
Bellagamba, et al. Standards Track [Page 6]
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If an intermediate point is meant to originate FMS messages, this
means that such an intermediate point is associated with a Server MEP
through a co-located MPLS-TP client/server adaptation function, and
the Fault Management subscription flag in the MPLS OAM FMS sub-TLV
has been set as an indication of the request to create the
association at each intermediate node of the client LSP. The
corresponding Server MEP needs to be configured by its own LSP Ping
session or, alternatively, via a Network Management System (NMS) or
RSVP-TE.
2.2. MPLS OAM Functions TLV
The MPLS OAM Functions TLV presented in Figure 1 is carried as a TLV
of the MPLS Echo Request/Reply messages [RFC4379].
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MPLS OAM Func. Type (27) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MPLS OAM Function Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ sub-TLVs ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: MPLS OAM Functions TLV Format
The MPLS OAM Functions TLV contains the MPLS OAM Function Flags
field. The MPLS OAM Function Flags indicate which OAM functions
should be activated as well as OAM function-specific sub-TLVs with
configuration parameters for the particular function.
Type: Indicates the MPLS OAM Functions TLV (Section 4).
Length: The length of the MPLS OAM Function Flags field including the
total length of the sub-TLVs in octets.
MPLS OAM Function Flags: A bitmap numbered from left to right as
shown in Figure 2. These flags are managed by IANA (refer to
Section 4.2). Flags defined in this document are presented in
Table 2. Undefined flags MUST be set to zero and unknown flags MUST
be ignored. The flags indicate what OAM is being configured and
direct the presence of optional sub-TLVs as set out below.
Bellagamba, et al. Standards Track [Page 7]
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|C|V|F|L|D|T|Unassigned MUST be zero (MBZ) |R|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: MPLS OAM Function Flags Format
Sub-TLVs corresponding to the different flags are as follows. No
meaning should be attached to the order of sub-TLVs.
o If a flag in the MPLS OAM Function Flags is set and the
corresponding sub-TLVs listed below are absent, then this MPLS OAM
function MUST be initialized according to its default settings.
Default settings of MPLS OAM functions are outside the scope of
this document.
o If any sub-TLV is present without the corresponding flag being
set, the sub-TLV SHOULD be ignored.
o BFD Configuration sub-TLV, which MUST be included if either the
CC, the CV, or both MPLS OAM Function flags are being set in the
MPLS OAM Functions TLV.
o Performance Monitoring sub-TLV MUST be used to carry PM Loss sub-
TLV and/or PM Delay sub-TLV. If neither one of these sub-TLVs is
present, then Performance Monitoring sub-TLV SHOULD NOT be
included. Empty, i.e., no enclosed sub-TLVs, Performance
Monitoring sub-TLV SHOULD be ignored.
o PM Loss sub-TLV MAY be included if the PM/Loss OAM Function flag
is set. If the "PM Loss sub-TLV" is not included, default
configuration values are used. Such sub-TLV MAY also be included
in case the Throughput function flag is set and there is the need
to specify a measurement interval different from the default ones.
In fact, the throughput measurement makes use of the same tool as
the loss measurement; hence, the same TLV is used.
o PM Delay sub-TLV MAY be included if the PM/Delay OAM Function flag
is set. If the "PM Delay sub-TLV" is not included, default
configuration values are used.
o FMS sub-TLV, that MAY be included if the FMS OAM Function flag is
set. If the "FMS sub-TLV" is not included, default configuration
values are used.
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If all flags in the MPLS OAM Function Flags field have the same value
of zero, that MUST be interpreted as meaning that the MPLS OAM
Functions TLV is not present in the MPLS Echo Request. If more than
one MPLS OAM Functions TLV is present in the MPLS Echo request
packet, then the first TLV SHOULD be processed and the rest ignored.
Any parsing error within nested sub-TLVs that is not specified in
Section 3 SHOULD be treated as described in [RFC4379].
2.2.1. BFD Configuration Sub-TLV
The BFD Configuration sub-TLV, depicted in Figure 3, is defined for
BFD OAM-specific configuration parameters. The "BFD Configuration
sub-TLV" is carried as a sub-TLV of the "OAM Functions TLV".
This TLV accommodates generic BFD OAM information and carries sub-
TLVs.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BFD Conf. Sub-type (100) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Vers.|N|S|I|G|U|B| Reserved (set to all 0s) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ sub-TLVs ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: BFD Configuration Sub-TLV Format
Sub-type: Indicates a new sub-type, the BFD Configuration sub-TLV
(value 100).
Length: Indicates the length of the Value field in octets.
Version: Identifies the BFD protocol version. If a node does not
support a specific BFD version, an error must be generated: "OAM
Problem/Unsupported BFD Version".
BFD Negotiation (N): If set, timer negotiation/renegotiation via BFD
Control Messages is enabled. When cleared, it is disabled and timer
configuration is achieved using the BFD Negotiation Timer Parameters
sub-TLV as described in Section 2.2.3.
Symmetric session (S): If set, the BFD session MUST use symmetric
timing values. If cleared, the BFD session MAY use any timing values
either negotiated or explicitly configured.
Bellagamba, et al. Standards Track [Page 9]
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Integrity (I): If set, BFD Authentication MUST be enabled. If the
BFD Configuration sub-TLV does not include a BFD Authentication sub-
TLV, the authentication MUST use Keyed SHA1 with an empty pre-shared
key (all 0s). If the egress LSR does not support BFD Authentication,
an error MUST be generated: "OAM Problem/BFD Authentication
unsupported". If the Integrity flag is clear, then Authentication
MUST NOT be used.
Encapsulation Capability (G): If set, it shows the capability of
encapsulating BFD messages into the G-ACh channel. If both the G bit
and U bit are set, configuration gives precedence to the G bit.
Encapsulation Capability (U): If set, it shows the capability of
encapsulating BFD messages into IP/UDP packets. If both the G bit
and U bit are set, configuration gives precedence to the G bit.
If the egress LSR does not support any of the ingress LSR
Encapsulation Capabilities, an error MUST be generated: "OAM Problem/
Unsupported BFD Encapsulation format".
Bidirectional (B): If set, it configures BFD in the Bidirectional
mode. If it is not set, it configures BFD in the unidirectional
mode. In the second case, the source node does not expect any
Discriminator values back from the destination node.
Reserved: Reserved for future specification; set to 0 on transmission
and ignored when received.
The BFD Configuration sub-TLV MUST include the following sub-TLVs in
the MPLS Echo Request message:
o BFD Local Discriminator sub-TLV, if the B flag is set in the MPLS
Echo Request;
o BFD Negotiation Timer Parameters sub-TLV, if the N flag is
cleared.
The BFD Configuration sub-TLV MUST include the following sub-TLVs in
the MPLS Echo Reply message:
o BFD Local Discriminator sub-TLV;
o BFD Negotiation Timer Parameters sub-TLV if:
* The N and S flags are cleared, or if:
* The N flag is cleared and the S flag is set, and the BFD
Negotiation Timer Parameters sub-TLV received by the egress
Bellagamba, et al. Standards Track [Page 10]
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contains unsupported values. In this case, an updated BFD
Negotiation Timer Parameters sub-TLV, containing values
supported by the egress node [RFC7419], is returned to the
ingress.
2.2.2. BFD Local Discriminator Sub-TLV
The BFD Local Discriminator sub-TLV is carried as a sub-TLV of the
"BFD Configuration sub-TLV" and is depicted in Figure 4.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Locl. Discr. Sub-type (101) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local Discriminator |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: BFD Local Discriminator Sub-TLV Format
Sub-type: Indicates a new sub-type, the "BFD Local Discriminator sub-
TLV" (value 101).
Length: Indicates the length of the Value field in octets (4).
Local Discriminator: A nonzero discriminator value that is unique in
the context of the transmitting system that generates it. It is used
to demultiplex multiple BFD sessions between the same pair of
systems.
2.2.3. BFD Negotiation Timer Parameters Sub-TLV
The BFD Negotiation Timer Parameters sub-TLV is carried as a sub-TLV
of the BFD Configuration sub-TLV and is depicted in Figure 5.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Nego. Timer Sub-type (102) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Acceptable Min. Asynchronous TX interval |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Acceptable Min. Asynchronous RX interval |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Required Echo TX Interval |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: BFD Negotiation Timer Parameters Sub-TLV Format
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Sub-type: Indicates a new sub-type, the BFD Negotiation Timer
Parameters sub-TLV (value 102).
Length: Indicates the length of the Value field in octets (12).
Acceptable Min. Asynchronous TX interval: If the S (symmetric) flag
is set in the BFD Configuration sub-TLV, defined in Section 2.2.1, it
expresses the desired time interval (in microseconds) at which the
ingress LER intends to both transmit and receive BFD periodic control
packets. If the receiving edge LSR cannot support such a value, it
SHOULD reply with an interval greater than the one proposed.
If the S (symmetric) flag is cleared in the BFD Configuration sub-
TLV, this field expresses the desired time interval (in microseconds)
at which an edge LSR intends to transmit BFD periodic control packets
in its transmitting direction.
Acceptable Min. Asynchronous RX interval: If the S (symmetric) flag
is set in the BFD Configuration sub-TLV, Figure 3, this field MUST be
equal to Acceptable Min. Asynchronous TX interval and has no
additional meaning respect to the one described for "Acceptable Min.
Asynchronous TX interval".
If the S (symmetric) flag is cleared in the BFD Configuration sub-
TLV, it expresses the minimum time interval (in microseconds) at
which edge LSRs can receive BFD periodic control packets. If this
value is greater than the value of Acceptable Min. Asynchronous TX
interval received from the other edge LSR, such an edge LSR MUST
adopt the interval expressed in this Acceptable Min. Asynchronous RX
interval.
Required Echo TX Interval: The minimum interval (in microseconds)
between received BFD Echo packets that this system is capable of
supporting, less any jitter applied by the sender as described in
Section 6.8.9 of [RFC5880]. This value is also an indication for the
receiving system of the minimum interval between transmitted BFD Echo
packets. If this value is zero, the transmitting system does not
support the receipt of BFD Echo packets. If the receiving system
cannot support this value, the "Unsupported BFD TX Echo rate
interval" error MUST be generated. By default, the value is set to
0.
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2.2.4. BFD Authentication Sub-TLV
The "BFD Authentication sub-TLV" is carried as a sub-TLV of the "BFD
Configuration sub-TLV" and is depicted in Figure 6.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BFD Auth. Sub-type (103) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Auth Type | Auth Key ID | Reserved (0s) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: BFD Authentication Sub-TLV Format
Sub-type: Indicates a new sub-type, the BFD Authentication sub-TLV
(value 103).
Length: Indicates the length of the Value field in octets (4).
Auth Type: Indicates which type of authentication to use. The same
values as are defined in Section 4.1 of [RFC5880] are used. Simple
Password SHOULD NOT be used if other authentication types are
available.
Auth Key ID: Indicates which authentication key or password
(depending on Auth Type) should be used. How the key exchange is
performed is out of scope of this document. If the egress LSR does
not support this Auth Key ID, an "OAM Problem/Mismatch of BFD
Authentication Key ID" error MUST be generated.
Reserved: Reserved for future specification; set to 0 on transmission
and ignored when received.
An implementation MAY change the mode of authentication if an
operator re-evaluates the security situation in and around the
administrative domain. If the BFD Authentication sub-TLV is used for
a BFD session in Up state, then the Sender of the MPLS LSP Echo
Request SHOULD ensure that old and new modes of authentication, i.e.,
a combination of Auth.Type and Auth. Key ID, are used to send and
receive BFD control packets, until the Sender can confirm that its
peer has switched to the new authentication.
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2.2.5. Traffic Class Sub-TLV
The Traffic Class sub-TLV is carried as a sub-TLV of the "BFD
Configuration sub-TLV" and "Fault Management Signal Sub-TLV"
(Section 2.2.9) and is depicted in Figure 7.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Traffic Class Sub-type (104) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TC | Reserved (set to all 0s) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 7: Traffic Class Sub-TLV Format
Sub-type: Indicates a new sub-type, the "Traffic Class sub-TLV"
(value 104).
Length: Indicates the length of the Value field in octets (4).
TC: Identifies the Traffic Class (TC) [RFC5462] for periodic
continuity monitoring messages or packets with fault management
information.
If the TC sub-TLV is present, then the sender of any periodic
continuity monitoring messages or packets with fault management
information on the LSP, with a Forwarding Equivalence Class (FEC)
that corresponds to the FEC for which fault detection is being
performed, MUST use the value contained in the TC field of the sub-
TLV as the value of the TC field in the top label stack entry of the
MPLS label stack. If the TC sub-TLV is absent from either "BFD
Configuration sub-TLV" or "Fault Management Signal sub-TLV", then
selection of the TC value is a local decision.
2.2.6. Performance Monitoring Sub-TLV
If the MPLS OAM Functions TLV has any of the L (Loss), D (Delay), and
T (Throughput) flags set, the Performance Monitoring sub-TLV MUST be
present. Failure to include the correct sub-TLVs MUST result in an
"OAM Problem/PM Configuration Error" being generated.
The Performance Monitoring sub-TLV provides the configuration
information mentioned in Section 7 of [RFC6374]. It includes support
for the configuration of quality thresholds and, as described in
[RFC6374]:
Bellagamba, et al. Standards Track [Page 14]
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...the crossing of which will trigger warnings or alarms, and
result in reporting and exception notification will be integrated
into the system-wide network management and reporting framework.
In case the values need to be different than the default ones, the
Performance Monitoring sub-TLV MAY include the following sub-TLVs:
o PM Loss sub-TLV, if the L flag is set in the MPLS OAM Functions
TLV;
o PM Delay sub-TLV, if the D flag is set in the MPLS OAM Functions
TLV.
The Performance Monitoring sub-TLV depicted in Figure 8 is carried as
a sub-TLV of the MPLS OAM Functions TLV.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Perf. Monitoring Sub-type (200)| Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PM Configuration Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ sub-TLVs ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 8: Performance Monitoring Sub-TLV Format
Sub-type: Indicates a new sub-type, the Performance Monitoring sub-
TLV (value 200).
Length: Indicates the length of the Value field in octets, including
PM Configuration Flags and optional sub-TLVs.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|D|L|J|Y|K|C| Reserved (set to all 0s) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 9: PM Configuration Flags Format
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The PM Configuration Flags format is presented in Figure 9. For the
specific function description, please refer to [RFC6374]:
D: Delay inferred/direct (0=INFERRED, 1=DIRECT). If the egress
LSR does not support the specified mode, an "OAM Problem/
Unsupported Delay Mode" error MUST be generated.
L: Loss inferred/direct (0=INFERRED, 1=DIRECT). If the egress LSR
does not support the specified mode, an "OAM Problem/
Unsupported Loss Mode" error MUST be generated.
J: Delay variation/jitter (1=ACTIVE, 0=NOT ACTIVE). If the egress
LSR does not support Delay variation measurements and the J
flag is set, an "OAM Problem/Delay variation unsupported" error
MUST be generated.
Y: Dyadic (1=ACTIVE, 0=NOT ACTIVE). If the egress LSR does not
support Dyadic mode and the Y flag is set, an "OAM Problem/
Dyadic mode unsupported" error MUST be generated.
K: Loopback (1=ACTIVE, 0=NOT ACTIVE). If the egress LSR does not
support Loopback mode and the K flag is set, an "OAM Problem/
Loopback mode unsupported" error MUST be generated.
C: Combined (1=ACTIVE, 0=NOT ACTIVE). If the egress LSR does not
support Combined mode and the C flag is set, an "OAM Problem/
Combined mode unsupported" error MUST be generated.
Reserved: Reserved for future specification; set to 0 on
transmission and ignored when received.
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2.2.7. PM Loss Measurement Sub-TLV
The PM Loss Measurement sub-TLV depicted in Figure 10 is carried as a
sub-TLV of the Performance Monitoring sub-TLV.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PM Loss Sub-type (201) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OTF |T|B| Reserved (set to all 0s) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Measurement Interval |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Test Interval |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Loss Threshold |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 10: PM Loss Measurement Sub-TLV Format
Sub-type: Indicates a new sub-type, the PM Loss Measurement sub-TLV
(value 201).
Length: Indicates the length of the Value field in octets (16).
OTF: Origin Timestamp Format of the Origin Timestamp field described
in [RFC6374]. By default, it is set to IEEE 1588 version 1. If the
egress LSR cannot support this value, an "OAM Problem/Unsupported
Timestamp Format" error MUST be generated.
Configuration Flags, please refer to [RFC6374] for further details:
T: Traffic-class-specific measurement indicator. Set to 1 when
the measurement operation is scoped to packets of a particular
traffic class (Differentiated Services Code Point value), and 0
otherwise. When set to 1, the Differentiated Services (DS)
field of the message indicates the measured traffic class. By
default, it is set to 1.
B: Octet (byte) count. When set to 1, indicates that the Counter
1-4 fields represent octet counts. When set to 0, indicates
that the Counter 1-4 fields represent packet counts. By
default, it is set to 0.
Reserved: Reserved for future specification; set to 0 on transmission
and ignored when received.
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Measurement Interval: The time interval (in milliseconds) at which
Loss Measurement query messages MUST be sent on both directions. If
the edge LSR receiving the Path message cannot support such a value,
it SHOULD reply with a higher interval. By default, it is set to
(100) as per [RFC6375].
Test Interval: Test messages interval in milliseconds as described in
[RFC6374]. By default, it is set to (10) as per [RFC6375].
Loss Threshold: The threshold value of measured lost packets per
measurement over which action(s) SHOULD be triggered.
2.2.8. PM Delay Measurement Sub-TLV
The "PM Delay Measurement sub-TLV" depicted in Figure 11 is carried
as a sub-TLV of the Performance Monitoring sub-TLV.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PM Delay Sub-type (202) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OTF |T|B| Reserved (set to all 0s) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Measurement Interval |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Test Interval |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Delay Threshold |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 11: PM Delay Measurement Sub-TLV Format
Sub-type: Indicates a new sub-type, the "PM Delay Measurement sub-
TLV" (value 202).
Length: Indicates the length of the Value field in octets (16).
OTF: Origin Timestamp Format of the Origin Timestamp field described
in [RFC6374]. By default, it is set to IEEE 1588 version 1. If the
egress LSR cannot support this value, an "OAM Problem/Unsupported
Timestamp Format" error MUST be generated.
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Configuration Flags, please refer to [RFC6374] for further details:
T: Traffic-class-specific measurement indicator. Set to 1 when
the measurement operation is scoped to packets of a particular
traffic class (Differentiated Services Code Point value), and 0
otherwise. When set to 1, the DS field of the message
indicates the measured traffic class. By default, it is set to
1.
B: Octet (byte) count. When set to 1, indicates that the Counter
1-4 fields represent octet counts. When set to 0, indicates
that the Counter 1-4 fields represent packet counts. By
default, it is set to 0.
Reserved: Reserved for future specification; set to 0 on transmission
and ignored when received.
Measurement Interval: The time interval (in milliseconds) at which
Delay Measurement query messages MUST be sent on both directions. If
the edge LSR receiving the Path message cannot support such a value,
it can reply with a higher interval. By default, it is set to (1000)
as per [RFC6375].
Test Interval: Test messages interval (in milliseconds) as described
in [RFC6374]. By default, it is set to (10) as per [RFC6375].
Delay Threshold: The threshold value of measured two-way delay (in
milliseconds) over which action(s) SHOULD be triggered.
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2.2.9. Fault Management Signal Sub-TLV
The FMS sub-TLV depicted in Figure 12 is carried as a sub-TLV of the
MPLS OAM Configuration sub-TLV. When both working and protection
paths are configured, both LSPs SHOULD be configured with identical
settings of the E flag, T flag, and the refresh timer. An
implementation MAY configure the working and protection LSPs with
different settings of these fields in case of 1:N protection.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FMS Sub-type (300) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|E|S|T| Reserved | Refresh Timer |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ sub-TLVs ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 12: Fault Management Signal Sub-TLV Format
Sub-type: Indicates a new sub-type, the FMS sub-TLV (value 300).
Length: Indicates the length of the Value field in octets.
FMS Flags are used to enable the FMS Flags at end point MEPs and the
Server MEPs of the links over which the LSP is forwarded. In this
document, only the S flag pertains to Server MEPs.
The following flags are defined:
E: Enable Alarm Indication Signal (AIS) and Lock Report (LKR)
signaling as described in [RFC6427]. Default value is 1
(enabled). If the egress MEP does not support FMS Flag
generation, an "OAM Problem/Fault management signaling
unsupported" error MUST be generated.
S: Indicate to a Server MEP that it should transmit AIS and LKR
signals on the client LSP. Default value is 0 (disabled). If
a Server MEP that is capable of generating FMS messages is, for
some reason, unable to do so for the LSP being signaled, an
"OAM Problem/Unable to create fault management association"
error MUST be generated.
T: Set timer value, enabled the configuration of a specific timer
value. Default value is 0 (disabled).
Bellagamba, et al. Standards Track [Page 20]
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Reserved: Bits 4-16 that follow the FMS Flags are reserved for future
allocation. These bits MUST be set to 0 on transmit and ignored on
receipt if not allocated.
Refresh Timer: Indicates the refresh timer of fault indication
messages, in seconds. The value MUST be between 1 to 20 seconds as
specified for the Refresh Timer field in [RFC6427]. If the edge LSR
receiving the Path message cannot support the value, it SHOULD reply
with a higher timer value.
FMS sub-TLV MAY include Traffic Class sub-TLV (Section 2.2.5). If
the TC sub-TLV is present, the value of the TC field MUST be used as
the value of the TC field of an MPLS label stack entry for FMS
messages. If the TC sub-TLV is absent, then selection of the TC
value is a local decision.
2.2.10. Source MEP-ID Sub-TLV
The Source MEP-ID sub-TLV depicted in Figure 13 is carried as a sub-
TLV of the MPLS OAM Functions TLV.
Note that support of ITU IDs is out of scope.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source MEP-ID Sub-type (400) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Node ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tunnel ID | LSP ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 13: Source MEP-ID Sub-TLV Format
Sub-type: Indicates a new sub-type, the Source MEP-ID sub-TLV (value
400).
Length: Indicates the length of the Value field in octets (8).
Source Node ID: 32-bit node identifier as defined in [RFC6370].
Tunnel ID: A 16-bit unsigned integer unique to the node as defined in
[RFC6370].
LSP ID: A 16-bit unsigned integer unique within the Tunnel_ID as
defined in [RFC6370].
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3. Summary of MPLS OAM Configuration Errors
This is the summary of Return Codes [RFC4379] defined in this
document:
o If an egress LSR does not support the specified BFD version, an
error MUST be generated: "OAM Problem/Unsupported BFD Version".
o If an egress LSR does not support the specified BFD Encapsulation
format, an error MUST be generated: "OAM Problem/Unsupported BFD
Encapsulation format".
o If an egress LSR does not support BFD Authentication, and it is
requested, an error MUST be generated: "OAM Problem/BFD
Authentication unsupported".
o If an egress LSR does not support the specified BFD Authentication
Type, an error MUST be generated: "OAM Problem/Unsupported BFD
Authentication Type".
o If an egress LSR is not able to use the specified Authentication
Key ID, an error MUST be generated: "OAM Problem/Mismatch of BFD
Authentication Key ID".
o If PM flags in MPLS OAM Functions TLV don't have corresponding PM
sub-TLVs present, an error MUST be generated: "OAM Problem/PM
Configuration Error".
o If an egress LSR does not support the specified Timestamp Format,
an error MUST be generated: "OAM Problem/Unsupported Timestamp
Format".
o If an egress LSR does not support specified Delay mode, an "OAM
Problem/Unsupported Delay Mode" error MUST be generated.
o If an egress LSR does not support specified Loss mode, an "OAM
Problem/Unsupported Loss Mode" error MUST be generated.
o If an egress LSR does not support Delay variation measurements,
and it is requested, an "OAM Problem/Delay variation unsupported"
error MUST be generated.
o If an egress LSR does not support Dyadic mode, and it is
requested, an "OAM Problem/Dyadic mode unsupported" error MUST be
generated.
Bellagamba, et al. Standards Track [Page 22]
RFC 7759 Extensions for MPLS-TP OAM Config. February 2016
o If an egress LSR does not support Loopback mode, and it is
requested, an "OAM Problem/Loopback mode unsupported" error MUST
be generated.
o If an egress LSR does not support Combined mode, and it is
requested, an "OAM Problem/Combined mode unsupported" error MUST
be generated.
o If an egress LSR does not support Fault Monitoring Signals, and it
is requested, an "OAM Problem/Fault management signaling
unsupported" error MUST be generated.
o If an intermediate Server MEP supports Fault Monitoring Signals,
but is unable to create an association, when requested to do so,
an "OAM Problem/Unable to create fault management association"
error MUST be generated.
Ingress LSR MAY combine multiple MPLS OAM configuration TLVs and sub-
TLVs into single MPLS echo request. In case an egress LSR doesn't
support any of the requested modes, it MUST set the return code to
report the first unsupported mode in the list of TLVs and sub-TLVs.
And if any of the requested OAM configuration is not supported, the
egress LSR SHOULD NOT process OAM Configuration TLVs and sub-TLVs
listed in the MPLS echo request.
4. IANA Considerations
4.1. TLV and Sub-TLV Allocation
IANA maintains the "Multi-Protocol Label Switching (MPLS) Label
Switched Paths (LSPs) Ping Parameters" registry and, within that
registry, a subregistry for TLVs and sub-TLVs.
IANA has allocated a new MPLS OAM Functions TLV from the Standards
Action [RFC5226] range (0-16383) and sub-TLVs as follows from
subregistry presented in Table 1, called "Sub-TLVs for TLV Type 27".
Registration procedures for Sub-TLVs from ranges 0-16383 and
32768-49161 are by Standards Action. Ranges 16384-31743 and
49162-64511 are through Specification Required (Experimental RFC
Needed).
Bellagamba, et al. Standards Track [Page 23]
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+------+----------+---------------------------------+---------------+
| Type | Sub-type | Value Field | Reference |
+------+----------+---------------------------------+---------------+
| 27 | | MPLS OAM Functions | This document |
| | 100 | BFD Configuration | This document |
| | 101 | BFD Local Discriminator | This document |
| | 102 | BFD Negotiation Timer | This document |
| | | Parameters | |
| | 103 | BFD Authentication | This document |
| | 104 | Traffic Class | This document |
| | 200 | Performance Monitoring | This document |
| | 201 | PM Loss Measurement | This document |
| | 202 | PM Delay Measurement | This document |
| | 300 | Fault Management Signal | This document |
| | 400 | Source MEP-ID | This document |
+------+----------+---------------------------------+---------------+
Table 1: IANA TLV Type Allocation
4.2. MPLS OAM Function Flags Allocation
IANA has created a new registry called the "MPLS OAM Function Flags"
registry. Assignments of bit positions 0 through 31 are via
Standards Action. The new registry is to be populated as follows.
+------------+--------------------+---------------------------------+
| Bit | MPLS OAM Function | Description |
| Position | Flag | |
+------------+--------------------+---------------------------------+
| 0 | C | Continuity Check (CC) |
| 1 | V | Connectivity Verification (CV) |
| 2 | F | Fault Management Signal (FMS) |
| 3 | L | Performance Monitoring/Loss |
| | | (PM/Loss) |
| 4 | D | Performance Monitoring/Delay |
| | | (PM/Delay) |
| 5 | T | Throughput Measurement |
| 6-30 | | Unassigned (Must be zero) |
| 31 | | Reserved |
+------------+--------------------+---------------------------------+
Table 2: MPLS OAM Function Flags
Bellagamba, et al. Standards Track [Page 24]
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4.3. OAM Configuration Errors
IANA maintains a registry "Multi-Protocol Label Switching (MPLS)
Label Switched Paths (LSPs) Ping Parameters", and within that
registry a subregistry "Return Codes".
IANA has assigned new Return Codes from the Standards Action range
(0-191) as follows:
+----------------+--------------------------------------+-----------+
| Error Value | Description | Reference |
| Sub-codes | | |
+----------------+--------------------------------------+-----------+
| 21 | OAM Problem/Unsupported BFD Version | This |
| | | document |
| 22 | OAM Problem/Unsupported BFD | This |
| | Encapsulation format | document |
| 23 | OAM Problem/Unsupported BFD | This |
| | Authentication Type | document |
| 24 | OAM Problem/Mismatch of BFD | This |
| | Authentication Key ID | document |
| 25 | OAM Problem/Unsupported Timestamp | This |
| | Format | document |
| 26 | OAM Problem/Unsupported Delay Mode | This |
| | | document |
| 27 | OAM Problem/Unsupported Loss Mode | This |
| | | document |
| 28 | OAM Problem/Delay variation | This |
| | unsupported | document |
| 29 | OAM Problem/Dyadic mode unsupported | This |
| | | document |
| 30 | OAM Problem/Loopback mode | This |
| | unsupported | document |
| 31 | OAM Problem/Combined mode | This |
| | unsupported | document |
| 32 | OAM Problem/Fault management | This |
| | signaling unsupported | document |
| 33 | OAM Problem/Unable to create fault | This |
| | management association | document |
| 34 | OAM Problem/PM Configuration Error | This |
| | | document |
+----------------+--------------------------------------+-----------+
Table 3: IANA Return Codes Allocation
Bellagamba, et al. Standards Track [Page 25]
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5. Security Considerations
The signaling of OAM-related parameters and the automatic
establishment of OAM entities introduces additional security
considerations to those discussed in [RFC4379]. In particular, a
network element could be overloaded if an attacker were to request
high-frequency liveliness monitoring of a large number of LSPs,
targeting a single network element. Implementations must be made
cognizant of available OAM resources and MAY refuse new OAM
configurations that would overload a node. Additionally, policies to
manage OAM resources may be used to provide some fairness in OAM
resource distribution among monitored LSPs.
Security of OAM protocols configured with extensions to LSP Ping
described in this document are discussed in [RFC5880], [RFC5884],
[RFC6374], [RFC6427], and [RFC6428].
In order that the configuration of OAM functionality can be achieved
securely through the techniques described in this document, security
mechanisms must already be in place and operational for LSP Ping.
Thus, the exchange of security parameters (such as keys) for use in
securing OAM is outside the scope of this document and is assumed to
use an off-line mechanism or an established secure key exchange
protocol.
Additional discussion of security for MPLS protocols can be found in
[RFC5920].
6. References
6.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC4379] Kompella, K. and G. Swallow, "Detecting Multi-Protocol
Label Switched (MPLS) Data Plane Failures", RFC 4379,
DOI 10.17487/RFC4379, February 2006,
<http://www.rfc-editor.org/info/rfc4379>.
[RFC5654] Niven-Jenkins, B., Ed., Brungard, D., Ed., Betts, M., Ed.,
Sprecher, N., and S. Ueno, "Requirements of an MPLS
Transport Profile", RFC 5654, DOI 10.17487/RFC5654,
September 2009, <http://www.rfc-editor.org/info/rfc5654>.
Bellagamba, et al. Standards Track [Page 26]
RFC 7759 Extensions for MPLS-TP OAM Config. February 2016
[RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010,
<http://www.rfc-editor.org/info/rfc5880>.
[RFC5884] Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow,
"Bidirectional Forwarding Detection (BFD) for MPLS Label
Switched Paths (LSPs)", RFC 5884, DOI 10.17487/RFC5884,
June 2010, <http://www.rfc-editor.org/info/rfc5884>.
[RFC6370] Bocci, M., Swallow, G., and E. Gray, "MPLS Transport
Profile (MPLS-TP) Identifiers", RFC 6370,
DOI 10.17487/RFC6370, September 2011,
<http://www.rfc-editor.org/info/rfc6370>.
[RFC6374] Frost, D. and S. Bryant, "Packet Loss and Delay
Measurement for MPLS Networks", RFC 6374,
DOI 10.17487/RFC6374, September 2011,
<http://www.rfc-editor.org/info/rfc6374>.
[RFC6427] Swallow, G., Ed., Fulignoli, A., Ed., Vigoureux, M., Ed.,
Boutros, S., and D. Ward, "MPLS Fault Management
Operations, Administration, and Maintenance (OAM)",
RFC 6427, DOI 10.17487/RFC6427, November 2011,
<http://www.rfc-editor.org/info/rfc6427>.
[RFC6428] Allan, D., Ed., Swallow Ed., G., and J. Drake Ed.,
"Proactive Connectivity Verification, Continuity Check,
and Remote Defect Indication for the MPLS Transport
Profile", RFC 6428, DOI 10.17487/RFC6428, November 2011,
<http://www.rfc-editor.org/info/rfc6428>.
6.2. Informative References
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001,
<http://www.rfc-editor.org/info/rfc3209>.
[RFC5036] Andersson, L., Ed., Minei, I., Ed., and B. Thomas, Ed.,
"LDP Specification", RFC 5036, DOI 10.17487/RFC5036,
October 2007, <http://www.rfc-editor.org/info/rfc5036>.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
DOI 10.17487/RFC5226, May 2008,
<http://www.rfc-editor.org/info/rfc5226>.
Bellagamba, et al. Standards Track [Page 27]
RFC 7759 Extensions for MPLS-TP OAM Config. February 2016
[RFC5462] Andersson, L. and R. Asati, "Multiprotocol Label Switching
(MPLS) Label Stack Entry: "EXP" Field Renamed to "Traffic
Class" Field", RFC 5462, DOI 10.17487/RFC5462, February
2009, <http://www.rfc-editor.org/info/rfc5462>.
[RFC5860] Vigoureux, M., Ed., Ward, D., Ed., and M. Betts, Ed.,
"Requirements for Operations, Administration, and
Maintenance (OAM) in MPLS Transport Networks", RFC 5860,
DOI 10.17487/RFC5860, May 2010,
<http://www.rfc-editor.org/info/rfc5860>.
[RFC5920] Fang, L., Ed., "Security Framework for MPLS and GMPLS
Networks", RFC 5920, DOI 10.17487/RFC5920, July 2010,
<http://www.rfc-editor.org/info/rfc5920>.
[RFC6371] Busi, I., Ed. and D. Allan, Ed., "Operations,
Administration, and Maintenance Framework for MPLS-Based
Transport Networks", RFC 6371, DOI 10.17487/RFC6371,
September 2011, <http://www.rfc-editor.org/info/rfc6371>.
[RFC6375] Frost, D., Ed. and S. Bryant, Ed., "A Packet Loss and
Delay Measurement Profile for MPLS-Based Transport
Networks", RFC 6375, DOI 10.17487/RFC6375, September 2011,
<http://www.rfc-editor.org/info/rfc6375>.
[RFC6669] Sprecher, N. and L. Fang, "An Overview of the Operations,
Administration, and Maintenance (OAM) Toolset for MPLS-
Based Transport Networks", RFC 6669, DOI 10.17487/RFC6669,
July 2012, <http://www.rfc-editor.org/info/rfc6669>.
[RFC7419] Akiya, N., Binderberger, M., and G. Mirsky, "Common
Interval Support in Bidirectional Forwarding Detection",
RFC 7419, DOI 10.17487/RFC7419, December 2014,
<http://www.rfc-editor.org/info/rfc7419>.
[RFC7487] Bellagamba, E., Takacs, A., Mirsky, G., Andersson, L.,
Skoldstrom, P., and D. Ward, "Configuration of Proactive
Operations, Administration, and Maintenance (OAM)
Functions for MPLS-Based Transport Networks Using RSVP-
TE", RFC 7487, DOI 10.17487/RFC7487, March 2015,
<http://www.rfc-editor.org/info/rfc7487>.
Acknowledgements
The authors would like to thank Nobo Akiya, David Allan, and Adrian
Farrel for their thorough reviews and insightful comments.
Bellagamba, et al. Standards Track [Page 28]
RFC 7759 Extensions for MPLS-TP OAM Config. February 2016
Authors' Addresses
Elisa Bellagamba
Email: elisa.bellagamba@gmail.com
Gregory Mirsky
Ericsson
Email: Gregory.Mirsky@ericsson.com
Loa Andersson
Huawei Technologies
Email: loa@mail01.huawei.com
Pontus Skoldstrom
Acreo AB
Electrum 236
Kista 164 40
Sweden
Phone: +46 8 6327731
Email: pontus.skoldstrom@acreo.se
Dave Ward
Cisco
Email: dward@cisco.com
John Drake
Juniper
Email: jdrake@juniper.net
Bellagamba, et al. Standards Track [Page 29]