TEAS Working Group
Internet Engineering Task Force (IETF) J. He
Internet-Draft
Request for Comments: 9270 I. Busi
Updates: 4872, 4873 (if approved) Huawei Technologies
Intended status:
Category: Standards Track J. Ryoo
Expires: October 21, 2022
ISSN: 2070-1721 B. Yoon
ETRI
P. Park
KT
April 19,
August 2022
GMPLS Signaling Extensions for Shared Mesh Protection
draft-ietf-teas-gmpls-signaling-smp-12
Abstract
ITU-T Recommendation G.808.3 defines the generic aspects of a Shared
Mesh Protection (SMP) mechanism, where the difference between SMP and
Shared Mesh Restoration (SMR) is also identified. ITU-T
Recommendation G.873.3 defines the protection switching operation and
associated protocol for SMP at the Optical Data Unit (ODU) layer.
RFC 7412 provides requirements for any mechanism that would be used
to implement SMP in a Multi-Protocol Label Switching - Transport
Profile (MPLS-TP) network.
This document updates RFC RFCs 4872 and RFC 4873 to provide the extensions
to the for
Generalized Multi-Protocol Label Switching (GMPLS) signaling to
support the control of the SMP. SMP mechanism.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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Internet-Drafts are draft documents valid the IETF community. It has
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Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of six months RFC 7841.
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This Internet-Draft will expire on October 21, 2022.
https://www.rfc-editor.org/info/rfc9270.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions Used in This Document . . . . . . . . . . . . . . 4
3. SMP Definition . . . . . . . . . . . . . . . . . . . . . . . 4
4. Operation of SMP with GMPLS Signaling Extension . . . . . . . 5 Extensions
5. GMPLS Signaling Extension Extensions for SMP . . . . . . . . . . . . . . 6
5.1. Identifiers . . . . . . . . . . . . . . . . . . . . . . . 7
5.2. Signaling Primary LSPs . . . . . . . . . . . . . . . . . 7
5.3. Signaling Secondary LSPs . . . . . . . . . . . . . . . . 7
5.4. SMP Preemption Priority . . . . . . . . . . . . . . . . . 8
5.5. Notifying Availability of Shared Resources . . . . . . . 8 Resources: The Notify Message
5.6. SMP APS Configuration . . . . . . . . . . . . . . . . . . 9
6. Updates to PROTECTION Object . . . . . . . . . . . . . . . . 10
6.1. New Protection Type . . . . . . . . . . . . . . . . . . . 10
6.2. Updates on to Definitions of Notification and Operational Bits . . . . . . 10
6.3. Preemption Priority . . . . . . . . . . . . . . . . . . . 11
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
8. Security Considerations . . . . . . . . . . . . . . . . . . . 11
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12
10. Contributor . . . . . . . . . . . . . . . . . . . . . . . . . 12
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
11.1.
9.1. Normative References . . . . . . . . . . . . . . . . . . 12
11.2.
9.2. Informative References . . . . . . . . . . . . . . . . . 13
Acknowledgements
Contributors
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction
RFC 4872 [RFC4872] defines extension of extensions for Resource Reservation
Protocol - Traffic Engineering (RSVP-TE) to support Shared Mesh
Restoration (SMR) mechanisms. SMR can be seen as a particular case
of pre-
planned preplanned Label Switched Path (LSP) rerouting that reduces the
recovery resource requirements by allowing multiple protecting LSPs
to share common link and node resources. The recovery resources for
the protecting LSPs are pre-reserved during the provisioning phase,
and explicit restoration signaling is required to activate (i.e.,
commit resource allocation at the data plane) a specific protecting
LSP that was instantiated during the provisioning phase. RFC 4873
[RFC4873] details the encoding of the last 32-bit Reserved field of
the PROTECTION object defined in [RFC4872] [RFC4872].
ITU-T Recommendation G.808.3 [G808.3] defines the generic aspects of
a shared mesh protection Shared Mesh Protection (SMP) mechanism, which are not specific to a
particular network technology in terms of architecture types,
preemption principle, and path monitoring methods, etc. ITU-T
Recommendation G.873.3 [G873.3] defines the protection switching
operation and associated protocol for SMP at the Optical Data Unit
(ODU) layer. RFC 7412 [RFC7412] provides requirements for any
mechanism that would be used to implement SMP in a Multi-Protocol
Label Switching - Transport Profile (MPLS-TP) network.
SMP differs from SMR in the activation/protection switching
operation. The former activates a protecting LSP via the automatic
protection switching Automatic
Protection Switching (APS) protocol in the data plane when the
working LSP fails, while the latter does it via control plane
signaling. It is therefore necessary to distinguish SMP from SMR
during provisioning so that each node involved behaves appropriately
in the recovery phase when activation of a protecting LSP is done.
SMP has advantages with regard to the recovery speed compared with
SMR.
This document updates [RFC4872] and [RFC4873] to provide the extensions to the
for Generalized Multi-Protocol Label Switching (GMPLS) signaling to
support the control of the SMP mechanism. Specifically,
it;
o it
* defines a new LSP protection type, Protection Type, "Shared Mesh Protection," Protection", for
the LSP Flags field [RFC4872] of the PROTECTION object (see
Section 6.1),
o
* updates the definitions of the Notification (N) and Operational
(O) fields [RFC4872] of the PROTECTION object to take the new SMP
type into account (see Section 6.2), and
o
* updates the definition of the 16-bit Reserved field [RFC4873] of
the PROTECTION object to allocate 8 bits to signal the SMP
preemption priority (see Section 6.3).
Only the generic aspects for signaling SMP are addressed by this
document. The technology-specific aspects are expected to be
addressed by other documents.
RFC 8776 [RFC8776] defines a collection of common YANG data types for
Traffic Engineering (TE) configuration and state capabilities. It
defines several identities for LSP protection types. Protection Types. As this
document introduces a new LSP Protection Type, [RFC8776] is expected
to be updated to support the SMP mechanism specified in this
document.
[I-D.ietf-teas-yang-te] [YANG-TE] defines a YANG data model for the provisioning
and management of TE tunnels, LSPs, and interfaces. It includes some
protection and restoration data nodes relevant to this document.
Management aspects of the SMP mechanism are outside the scope of this
document, and they are expected to be addressed by other documents.
2. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
In addition, the reader is assumed to be familiar with the
terminology used in [RFC4872], RFC 4426 [RFC4426], and RFC 6372
[RFC6372].
3. SMP Definition
[G808.3] defines the generic aspects of an SMP mechanism. [G873.3]
defines the protection switching operation and associated protocol
for SMP at the ODU layer. [RFC7412] provides requirements for any
mechanism that would be used to implement SMP in a an MPLS-TP network.
The SMP mechanism is based on pre-computed precomputed protecting LSPs that are
pre-configured
preconfigured into the network elements. Pre-configuration Preconfiguration here means
pre-reserving resources for the protecting LSPs without activating a
particular protecting LSP (e.g., in circuit networks, the cross-connects cross-
connects in the intermediate nodes of the protecting LSP are not pre-established). Pre-configuring
preestablished). Preconfiguring but not activating protecting LSPs
allows link and node resources to be shared by the protecting LSPs of
multiple working LSPs (that (which are themselves disjoint and thus
unlikely to fail simultaneously). Protecting LSPs are activated in
response to failures of working LSPs or operator's operator commands by means of
the APS protocol that protocol, which operates in the data plane. The APS protocol
messages are exchanged along the protecting LSP. SMP is always
revertive.
SMP has a lot of similarity is very similar to SMR SMR, except that the activation in the case of SMR
is achieved by control plane signaling during the recovery operation,
while SMP the same is done for SMP by the APS protocol in the data plane.
4. Operation of SMP with GMPLS Signaling Extension Extensions
Consider the following network topology: topology shown in Figure 1:
A---B---C---D
\ /
E---F---G
/ \
H---I---J---K
Figure 1: An example Example of an SMP topology Topology
The working LSPs [A,B,C,D] and [H,I,J,K] could be protected by the
protecting LSPs [A,E,F,G,D] and [H,E,F,G,K], respectively. Per RFC
3209 [RFC3209], in order to achieve resource sharing during the
signaling of these protecting LSPs, they MUST have the same Tunnel
Endpoint Address (as part of their SESSION object). However, these
addresses are not the same in this example. Similar to SMR, this
document defines a new LSP Protection Type of the secondary LSP as
"Shared Mesh Protection" (see Section 6.1) to allow resource sharing
along nodes E, F, and G. Examples of shared resources include the
capacity of a link and the cross-connects in a node. In this case,
the protecting LSPs are not merged (which is useful useful, since the paths
diverge at G), but the resources along E, F, and G can be shared.
When a failure, such as Signal Fail (SF) and or Signal Degrade (SD),
occurs on one of the working LSPs (say (say, working LSP [A,B,C,D]), the
end node (say (say, node A) that detects the failure initiates the
protection switching operation. End node A will send a protection
switching request APS message (for example, SF) to its adjacent
(downstream) intermediate node (say (say, node E) to activate the
corresponding protecting LSP and will wait for a confirmation message
from node E.
If the protection resource is available, node E will send the
confirmation APS message to the end node A (node A) and forward the
switching request APS message to its adjacent (downstream) node (say (say,
node F). When the confirmation APS message is received by node A,
the cross-
connection cross-connection on node A is established. At this time time, traffic
is bridged to and selected from the protecting LSP at node A. After
forwarding the switching request APS message, node E will wait for a
confirmation APS message from node F, which triggers node E to set up
the cross-connection for the protecting LSP being activated.
If the protection resource is not available (due to failure or being
used by higher priority higher-priority connections), the switching will not be
successful; the intermediate node (node E) MUST send a message to
notify the end node (node A) (see Section 5.5). If the resource is
in use by a lower priority lower-priority protecting LSP, the lower priority lower-priority service
will be removed removed, and then the intermediate node will then follow the
procedure as described for the case when the protection resource is
available for the higher priority higher-priority protecting LSP.
If node E fails to allocate the protection resource, it MUST send a
message to notify node A (see Section 5.5). Then, node A will stop
bridging and selecting traffic to/from the protecting LSP and proceed
with the procedure of removing the protection allocation according to
the APS protocol.
5. GMPLS Signaling Extension Extensions for SMP
The following subsections detail how LSPs using SMP can be signaled
in an interoperable fashion using GMPLS RSVP-TE extensions (see RFC
3473 [RFC3473]). This signaling enables:
(1) the ability to identify a "secondary protecting LSP" (LSP
[A,E,F,G,D] or LSP [H,E,F,G,K] from Figure 1, hereby here called the
"secondary LSP") used to recover another "primary working LSP"
(LSP [A,B,C,D] or LSP [H,I,J,K] from Figure 1, hereby here called the
"protected LSP"),
(2) the ability to associate the secondary LSP with the protected
LSP,
(3) the capability to include information about the resources used
by the protected LSP while instantiating the secondary LSP,
(4) the capability to instantiate during the provisioning phase several secondary LSPs efficiently, efficiently
during the provisioning phase, and
(5) the capability to support activation of a secondary LSP after
failure occurrence via the
APS protocol in the data plane. plane if a failure occurs.
5.1. Identifiers
To simplify association operations, both LSPs (i.e., the protected
LSP and the secondary LSPs) LSP) belong to the same session. Thus, the
SESSION object MUST be the same for both LSPs. The LSP ID, however,
MUST be different to distinguish between the protected LSP and the
secondary LSP.
A new LSP Protection Type Type, "Shared Mesh Protection" Protection", is defined (see
Section 6.1) for the LSP Flags field of the PROTECTION object (see
[RFC4872]) to set up the two LSPs. This LSP Protection Type value is applicable
only applicable to bidirectional LSPs as required in [G808.3].
5.2. Signaling Primary LSPs
The PROTECTION object (see [RFC4872]) is included in the Path message
during signaling of the primary working LSPs, with the LSP Protection
Type value set to "Shared Mesh Protection".
Primary working LSPs are signaled by setting in the PROTECTION object
the S bit to 0, the P bit to 0, and the N bit to 1, 1; and setting in
the ASSOCIATION object, object the Association ID to the associated secondary
protecting LSP_ID.
| Note: The N bit is set to indicate that the protection
| switching signaling is done via the data plane.
5.3. Signaling Secondary LSPs
The PROTECTION object (see [RFC4872]) is included in the Path message
during signaling of the secondary protecting LSPs, with the LSP
Protection Type value set to "Shared Mesh Protection".
Secondary protecting LSPs are signaled by setting in the PROTECTION
object the S bit, the P bit, and the N bit to 1, 1; and setting in the
ASSOCIATION object, object the Association ID to the associated primary
working LSP_ID, which MUST be known before signaling of the secondary
LSP. Moreover, the Path message used to instantiate the secondary
LSP MUST include at least one PRIMARY_PATH_ROUTE object (see
[RFC4872]) that further allows for recovery resource sharing at each
intermediate node along the secondary path.
With this setting, the resources for the secondary LSP MUST be pre-
reserved,
reserved but not committed at the data plane level, meaning that the
internals of the switch need not be established until explicit action
is taken to activate this LSP. Activation of a secondary LSP and
protection switching to the activated protecting LSP is done using
the APS protocol in the data plane.
After protection switching completes completes, the protecting LSP MUST be
signaled with by setting the S bit set to 0 and the O bit set to 1 in the
PROTECTION object. At this point, the link and node resources MUST
be allocated for this LSP that LSP, which becomes a primary LSP (ready to
carry traffic). The formerly working LSP MAY be signaled with the A
bit set in the ADMIN_STATUS object (see [RFC3473]).
Support for extra traffic in SMP is left for further study.
Therefore, mechanisms to set up LSPs for extra traffic are outside
the scope of this document.
5.4. SMP Preemption Priority
The SMP preemption priority of a protecting LSP that is used by the APS
protocol
uses to resolve the competition for shared resources among multiple
protecting LSPs, LSPs and is indicated in the Preemption Priority field of
the PROTECTION object in the Path message of the protecting LSP.
The Setup and Holding priorities in the SESSION_ATTRIBUTE object can
be used by GMPLS to control LSP preemption, but, but they are not used by
the APS to resolve the competition among multiple protecting LSPs. This
avoids the need to define a complex policy for defining Setup and
Holding priorities when used for both GMPLS control plane LSP
preemption and SMP shared resource competition resolution.
When an intermediate node on the protecting LSP receives the Path
message, the priority value in the Preemption Priority field MUST be
stored for that protecting LSP. When resource competition among
multiple protecting LSPs occurs, the APS protocol will use their
priority values to resolve the this competition. A lower value has a
higher priority.
In SMP, a preempted LSP MUST NOT be terminated even after its
resources have been deallocated. Once the working LSP and the
protecting LSP are configured or pre-configured, preconfigured, the end node MUST
keep refreshing both working and protecting LSPs LSPs, regardless of
failure or preempted situation. preemption status.
5.5. Notifying Availability of Shared Resources Resources: The Notify Message
When a lower priority lower-priority protecting LSP is preempted, the intermediate
node that performed the preemption MUST send a Notify message with
error code "Notify Error" (25) (see [RFC4872]) and error sub-code
"Shared resources unavailable" (TBA1) (17) to the end nodes of that
protecting LSP. Upon receipt of this Notify message, the end node
MUST stop sending and selecting traffic to/from its protecting LSP
and try switching the traffic to another protecting LSP, if
available.
When a protecting LSP occupies the shared resources and they become
unavailable, the same Notify message MUST be generated by the
intermediate node to all the end nodes of the protecting LSPs that
have lower SMP preemption priorities than the one that has occupied
the shared resources. In case If the shared resources become unavailable due
to a failure in the shared resources, the same Notify message MUST be
generated by the intermediate node to all the end nodes of the
protecting LSPs that have been configured to use the shared
resources. These end nodes, in In the case of a failure of the working LSP, these end
nodes MUST avoid trying to switch traffic to these protecting LSPs
that have been configured to use the shared resources and try
switching the traffic to other protecting LSPs, if available.
When the shared resources become available, a Notify message with
error code "Notify Error" (25) and error sub-code "Shared resources
available" (TBA2) (18) MUST be generated by the intermediate node. The
recipients of this Notify message are the end nodes of the lower lower-
priority protecting LSPs that have been preempted and/or all the end
nodes of the protecting LSPs that have lower SMP preemption
priorities than the one that does not need the shared resources
anymore. Upon receipt of this Notify message, the end node is
allowed to reinitiate the protection switching operation as described
in Section 4, if it still needs the protection resource.
5.6. SMP APS Configuration
SMP relies on APS protocol messages being exchanged between the nodes
along the path to activate an SMP a protecting LSP.
In order to allow the exchange of APS protocol messages, an APS
channel has to be configured between adjacent nodes along the path of
the SMP protecting LSP. This is done by other means other than GMPLS
signaling, before any SMP protecting LSP has been set up. Therefore,
there are likely additional requirements for APS configuration which that
are outside the scope of this document.
Depending on the APS protocol message format, the APS protocol may
use different identifiers than GMPLS signaling to identify the SMP
protecting LSP.
Since the APS protocol is left for further study in per [G808.3], it can
be assumed that the APS message format and identifiers are technology- technology
specific and/or vendor-specific. vendor specific. Therefore, additional requirements
for APS configuration are outside the scope of this document.
6. Updates to PROTECTION Object
GMPLS extension requirements for SMP introduce several updates to the
Protection Object
PROTECTION object (see [RFC4872]). [RFC4872]), as detailed below.
6.1. New Protection Type
A new LSP protection type Protection Type, "Shared Mesh Protection" Protection", is added in the
PROTECTION object. This LSP Protection Type value is only applicable
to
only bidirectional LSPs.
LSP (Protection Type) Flags:
0x20: Shared Mesh Protection
The rules defined in Section 14.2 of [RFC4872] ensure that all the
nodes along an SMP LSP are SMP aware. Therefore, there are no
backward compatibility
backward-compatibility issues.
6.2. Updates on to Definitions of Notification and Operational Bits
The definitions of the N and O bits in Section 14.1 of [RFC4872] are
replaced as follows:
Notification (N): 1 bit
When set to 1, this bit indicates that the control plane message
exchange is only used for notification during protection
switching. When set to 0 (default), it indicates that the control
plane message exchanges are used for protection-switching
purposes. purposes of protection
switching. The N bit is only applicable when the LSP Protection
Type Flag is set to 0x04 (1:N Protection with Extra-Traffic), 0x08
(1+1 Unidirectional Protection), 0x10 (1+1 Bidirectional
Protection), or 0x20 (Shared Mesh Protection). The N bit MUST be
set to 0 in any other case. If 0x20 (SMP), the N bit MUST be set
to 1.
Operational (O): 1 bit
When set to 1, this bit indicates that the protecting LSP is
carrying traffic after protection switching. The O bit is only
applicable when (1) the P bit is set to 1, 1 and (2) the LSP
Protection Type Flag is set to 0x04 (1:N Protection with Extra-Traffic), Extra-
Traffic), 0x08 (1+1 Unidirectional Protection), 0x10 (1+1
Bidirectional Protection), or 0x20 (Shared Mesh Protection). The
O bit MUST be set to 0 in any other case.
6.3. Preemption Priority
[RFC4872] reserved a 32-bit field in the PROTECTION object header.
Subsequently, [RFC4873] allocated several fields bits from that field, field and
left the remainder of the bits reserved. This specification further
allocates the preemption priority Preemption Priority field from those formerly-reserved the remaining formerly
reserved bits. The 32-bit field in the PROTECTION object as defined
in [RFC4872] and modified by [RFC4873]
are is updated by this document as
follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|I|R| Reserved | Seg.Flags | Reserved | Preempt Prio |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Preemption Priority (Preempt Prio): 8 bit bits
This field indicates the SMP preemption priority of a protecting
LSP, when the LSP Protection Type field indicates "Shared Mesh
Protection". The SMP preemption priority value is configured at
the end nodes of the protecting LSP by a network operator. A
lower value has a higher priority. The decision of regarding how
many priority levels to should be operated implemented in an SMP network is a
left to network
operator's choice. operators.
See [RFC4873] for the definition definitions of the other fields.
7. IANA Considerations
IANA maintains a registry group of registries called "Resource Reservation
Protocol (RSVP) Parameters" with a subregistry called Parameters", which includes the "Error Codes and
Globally-Defined Error Value Sub-Codes". Within this subregistry
there is a definition of Sub-Codes" registry. IANA has added the "Notify
following values to the "Sub-Codes - 25 Notify Error" error code (25). The
definition subregistry,
which lists a number of error value sub-codes that may be used with this error code. code
25. IANA is requested to allocate further has allocated the following error value sub-codes (Table 1)
for use with this error code as described in this document.
+=======+==============================+===========+
| Value | Description | Reference
----- ---------------------------- ---------------
TBA1 |
+=======+==============================+===========+
| 17 | Shared resources unavailable (this document)
TBA2 | RFC 9270 |
+-------+------------------------------+-----------+
| 18 | Shared resources available (this document) | RFC 9270 |
+-------+------------------------------+-----------+
Table 1: New Error Sub-Codes
8. Security Considerations
Since this document makes use of the exchange of RSVP messages
including that
include a Notify message, the security threats discussed in [RFC4872]
also apply to this document.
Additionally, it may be possible to cause disruption to traffic on
one protecting LSP by targeting a link used by the primary LSP of
another, higher priority higher-priority LSP somewhere completely different in the
network. For example, in Figure 1, assume that the preemption
priority of LSP [A,E,F,G,D] is higher than that of LSP [H,E,F,G,K]
and the protecting LSP [H,E,F,G,K] is being used to transport
traffic. If link B-C is attacked, traffic on LSP [H,E,F,G,K] can be
disrupted. For this reason, it is important not only to use security
mechanisms as discussed in [RFC4872] but also to acknowledge that
detailed knowledge of a network's topology, including routes and
priorities of LSPs, can help an attacker better target or improve the
efficacy of an attack.
9. Acknowledgements
The authors would like to thank Adrian Farrel, Vishnu Pavan Beeram,
Tom Petch, Ines Robles, John Scudder, Dale Worley, Dan Romascanu,
Eric Vyncke, Roman Danyliw, Paul Wouters, Lars Eggert, Francesca
Palombini, and Robert Wilton for their valuable comments and
suggestions on this document.
10. Contributor
The following person contributed significantly to the content of this
document and should be considered as a co-author.
Yuji Tochio
Fujitsu
Email: tochio@fujitsu.com
11. References
11.1.
9.1. Normative References
[G808.3] International Telecommunication Union, "Generic protection
switching - Shared mesh protection", ITU-T Recommendation
G.808.3, October 2012. 2012,
<https://www.itu.int/rec/T-REC-G.808.3>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[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,
<https://www.rfc-editor.org/info/rfc3209>.
[RFC3473] Berger, L., Ed., "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling Resource ReserVation Protocol-
Traffic Engineering (RSVP-TE) Extensions", RFC 3473,
DOI 10.17487/RFC3473, January 2003,
<https://www.rfc-editor.org/info/rfc3473>.
[RFC4426] Lang, J., Ed., Rajagopalan, B., Ed., and D. Papadimitriou,
Ed., "Generalized Multi-Protocol Label Switching (GMPLS)
Recovery Functional Specification", RFC 4426,
DOI 10.17487/RFC4426, March 2006,
<https://www.rfc-editor.org/info/rfc4426>.
[RFC4872] Lang, J., J P., Ed., Rekhter, Y., Ed., and D. Papadimitriou,
Ed., "RSVP-TE Extensions in Support of End-to-End
Generalized Multi-Protocol Label Switching (GMPLS)
Recovery", RFC 4872, DOI 10.17487/RFC4872, May 2007,
<https://www.rfc-editor.org/info/rfc4872>.
[RFC4873] Berger, L., Bryskin, I., Papadimitriou, D., and A. Farrel,
"GMPLS Segment Recovery", RFC 4873, DOI 10.17487/RFC4873,
May 2007, <https://www.rfc-editor.org/info/rfc4873>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
11.2.
9.2. Informative References
[G873.3] International Telecommunication Union, "Optical transport
network - Shared mesh protection", ITU-T Recommendation
G.873.3, September 2017.
[I-D.ietf-teas-yang-te]
Saad, T., Gandhi, R., Liu, X., Beeram, V. P., Bryskin, I.,
and O. G. D. Dios, "A YANG Data Model for Traffic
Engineering Tunnels, Label Switched Paths and Interfaces",
draft-ietf-teas-yang-te-29 (work in progress), February
2022. 2017,
<https://www.itu.int/rec/T-REC-G.873.3-201709-I/en>.
[RFC6372] Sprecher, N., Ed. and A. Farrel, Ed., "MPLS Transport
Profile (MPLS-TP) Survivability Framework", RFC 6372,
DOI 10.17487/RFC6372, September 2011,
<https://www.rfc-editor.org/info/rfc6372>.
[RFC7412] Weingarten, Y., Aldrin, S., Pan, P., Ryoo, J., and G.
Mirsky, "Requirements for MPLS Transport Profile (MPLS-TP)
Shared Mesh Protection", RFC 7412, DOI 10.17487/RFC7412,
December 2014, <https://www.rfc-editor.org/info/rfc7412>.
[RFC8776] Saad, T., Gandhi, R., Liu, X., Beeram, V., and I. Bryskin,
"Common YANG Data Types for Traffic Engineering",
RFC 8776, DOI 10.17487/RFC8776, June 2020,
<https://www.rfc-editor.org/info/rfc8776>.
[YANG-TE] Saad, T., Gandhi, R., Liu, X., Beeram, V.P., Bryskin, I.,
and O. Gonzalez de Dios, "A YANG Data Model for Traffic
Engineering Tunnels, Label Switched Paths and Interfaces",
Work in Progress, Internet-Draft, draft-ietf-teas-yang-te-
29, 7 February 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-teas-
yang-te-29>.
Acknowledgements
The authors would like to thank Adrian Farrel, Vishnu Pavan Beeram,
Tom Petch, Ines Robles, John Scudder, Dale Worley, Dan Romascanu,
Éric Vyncke, Roman Danyliw, Paul Wouters, Lars Eggert, Francesca
Palombini, and Robert Wilton for their valuable comments and
suggestions on this document.
Contributors
The following person contributed significantly to the content of this
document and should be considered a coauthor.
Yuji Tochio
Fujitsu
Email: tochio@fujitsu.com
Authors' Addresses
Jia He
Huawei Technologies
F3-1B, R&D Center, Huawei Industrial Base, Base
Bantian, Longgang District
Shenzhen
China
Email: hejia@huawei.com
Italo Busi
Huawei Technologies
Email: italo.busi@huawei.com
Jeong-dong Ryoo
ETRI
218 Gajeongno
Yuseong-gu,
Yuseong-gu
Daejeon
34129
South Korea
Phone: +82-42-860-5384
Email: ryoo@etri.re.kr
Bin Yeong Yoon
ETRI
Email: byyun@etri.re.kr
Peter Park
KT
Email: peter.park@kt.com