PCE Working Group

Internet Engineering Task Force (IETF)                    B. Rajagopalan
Internet-Draft
Request for Comments: 9863                                     V. Beeram
Intended status:
Category: Standards Track                               Juniper Networks
Expires: 30 August 2025
ISSN: 2070-1721                                                  S. Peng
                                                         ZTE Corporation
                                                            M. Koldychev
                                                       Ciena Corporation
                                                               G. Mishra
                                             Verizon Communications Inc.
                                                        26 February
                                                          September 2025

      Path Computation Element Protocol (PCEP) Extension for Color
                      draft-ietf-pce-pcep-color-12

Abstract

   Color is a 32-bit numerical (unsigned integer) attribute used to
   associate a Traffic Engineering (TE) tunnel or policy with an intent
   or objective.  For example, a TE Tunnel constructed to deliver low
   latency services and whose path is optimized for delay can be tagged
   with a color that represents "low latency."  This document specifies
   extensions to the Path Computation Element Protocol (PCEP) to carry
   the color attribute.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list  It represents the consensus of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid the IETF community.  It has
   received public review and has been approved for a maximum publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of six months RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be updated, replaced, or obsoleted by other documents obtained at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 30 August 2025.
   https://www.rfc-editor.org/info/rfc9863.

Copyright Notice

   Copyright (c) 2025 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  Protocol Operation  . . . . . . . . . . . . . . . . . . . . .   3
   3.  Protocol Extensions . . . . . . . . . . . . . . . . . . . . .   4
     3.1.  Color Capability  . . . . . . . . . . . . . . . . . . . .   4
     3.2.  Color TLV . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   5.  Manageability Considerations  . . . . . . . . . . . . . . . .   5
     5.1.  Control of Function through Configuration and Policy  . .   5
     5.2.  Information and Data Models . . . . . . . . . . . . . . .   5
     5.3.  Liveness Detection and Monitoring . . . . . . . . . . . .   5
     5.4.  Verifying Correct Operation . . . . . . . . . . . . . . .   6
     5.5.  Requirements on Other Protocols . . . . . . . . . . . . .   6
     5.6.  Impact on Network Operation . . . . . . . . . . . . . . .   6
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
     6.1.  PCEP TLV Type Indicator . . . . . . . . . . . . . . . . .   6
     6.2.  STATEFUL-PCE-CAPABILITY TLV Flag Field  . . . . . . . . .   6
     6.3.  PCEP-Error Object . . . . . . . . . . . . . . . . . . . .   6
     6.4.  LSP-ERROR-CODE TLV Error Code Field . . . . . . . . . . .   7
   7.  Implementation Status . . . . . . . . . . . . . . . . . . . .   7
   8.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   8
   9.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .   8
   10.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   8
     10.1.
     7.1.  Normative References . . . . . . . . . . . . . . . . . .   8
     10.2.
     7.2.  Informative References . . . . . . . . . . . . . . . . .   9
   Acknowledgments
   Contributors
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  11

1.  Introduction

   A Traffic Engineering (TE) tunnel ([RFC3209]) [RFC3209] or Segment Routing (SR)
   policy ([RFC9256]) [RFC9256] can be associated with an intent or objective (e.g.,
   low latency) by tagging it with a color.  This color attribute is
   used as a guiding criterion for mapping services onto the TE tunnel ([RFC9012])
   [RFC9012] or SR policy ([RFC9256]). [RFC9256].  The term color "color" used in this
   document must not be interpreted as the 'thread color' "thread color" specified in
   [RFC3063] or the 'resource color' "resource color" (also referred to as 'link
   color') "link color")
   specified in [RFC3630], [RFC5329], [RFC5305] [RFC5305], and [RFC7308].

   [RFC8231] specifies extensions to the Path Computation Element
   Protocol (PCEP) that enable the deployment of a stateful Path
   Computation Element (PCE) model.  These extensions allow a Path
   Computation Client (PCC) to delegate control of the Label Switched
   Paths (LSPs) associated with its TE Tunnels to a stateful PCE.
   [RFC8281] specifies extensions that allow a PCE to instantiate and
   manage PCE-initiated LSPs on a PCC under the stateful PCE model.
   [RFC8664] specifies extensions that enable stateful control of SR
   paths via PCEP.

   This document introduces extensions to PCEP to allow a color tag to
   be assigned to any TE path operated under a stateful PCE model
   (including those set up using RSVP-TE [RFC8408] or Segment Routing
   [RFC8664]).  The only exception where the extensions defined in this
   document MUST NOT be used to carry the color attribute is for SR
   paths established using the extensions defined in
   [I-D.ietf-pce-segment-routing-policy-cp]. [RFC9862].  For
   these SR paths, the associated color is already included as part of
   the SR policy identifier encoding.

   The mechanism employed by the PCC for mapping services onto a TE path
   associated with a color attribute is outside the scope of this
   document, as is any other use of the color tag.

1.1.  Requirements Language

   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.

2.  Protocol Operation

   When the PCEP session is created, a PCEP (PCE/PCC) speaker sends an
   Open message with an OPEN object that contains the STATEFUL-PCE-
   CAPABILITY TLV, as defined in [RFC8231].  A STATEFUL-PCE-CAPABILITY
   TLV Flag (See (see Section 3.1) is introduced in this document to enable
   the PCEP speaker to advertise color capability.

   In PCRpt, PCUpd, and PCInitiate messages, the LSP object ([RFC8231],
   [RFC8281]) [RFC8231]
   [RFC8281] is a mandatory inclusion and is used to carry information
   specific to the target LSP.  A TLV called the Color TLV (see
   Section 3.2), which MAY be carried in the LSP object, is introduced
   in this document to carry the color attribute associated with the
   LSP.  Only one COLOR TLV SHOULD be included in the LSP object.  If
   the COLOR TLV appears in the LSP object more than once, only the
   first occurrence is processed, and any others MUST be ignored.

   A PCEP speaker that has advertised color capability MUST NOT send
   Color TLV encoded in the LSP object to a PCEP Peer that has not
   advertised color capability.  A PCEP speaker that advertises both
   color capability and SR Policy Association [RFC9862] capability
   ([I-D.ietf-pce-segment-routing-policy-cp]) MUST
   NOT send Color TLV encoded in the LSP object for SR Paths.  The Color
   TLV is ignored if it shows up in the LSP object of a message which that
   carries an ASSOCIATION object of type SR Policy Association
   ([I-D.ietf-pce-segment-routing-policy-cp]).
   [RFC9862].  The color encoded in the SR Policy Association takes
   precedence in such a scenario.

   If a PCC is unable to honor a color value passed in a PCUpd or a
   PCInitiate message, the PCC MUST reject the message and send a PCErr
   message with Error-type=19 Error-Type=19 (Invalid Operation) and error-value=TBD1 Error-value=31
   (Invalid color).  This is expected behavior in scenarios where a PCC
   implementation does not support a color value of zero for specific
   path setup types, and it receives that value in the COLOR TLV of a
   PCUpd or a PCInitiate message.

   When LSPs that belong to the same TE tunnel are within the same Path
   Protection Association Group [RFC8745], they are all expected to have
   the same color attached to them.  If a PCEP speaker determines
   inconsistency in the color associated with the LSPs belonging to the
   same Path Protection Association Group, it MUST reject the message
   carrying the inconsistent color and send a PCErr message with Error-
   type=19
   Type=19 (Invalid Operation) and error-value=TBD2 Error-value=32 (Inconsistent color).

3.  Protocol Extensions

3.1.  Color Capability

   Section 7.1.1 of [RFC8231] defines STATEFUL-PCE-CAPABILITY TLV flags.
   The following flag is used to indicate if the speaker supports color
   capability:

   C-bit (Bit 20):  A PCE/PCC indicates that it supports the color
      capability defined in this document by setting this bit.

3.2.  Color TLV

      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |     Type                      |          Length=4             |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                             Color                             |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                            Figure 1: Color TLV

   Type has the value 67.  Length carries a value of 4.  The 'color' "Color"
   field is 4-bytes long, 4 bytes long and carries the actual color value (specified
   as an unsigned integer).  A color Color value of zero is allowed.

4.  Security Considerations

   This document defines a TLV for color and a flag for color capability
   negotiation, which do not add any security concerns beyond those
   discussed in [RFC5440], [RFC8231] [RFC8231], and [RFC8281].

   An unauthorized PCE may maliciously associate the LSP with an
   incorrect color.  The procedures described in [RFC8253] and [RFC9325]
   can be used to protect against this attack.

5.  Manageability Considerations

   This section follows the advice and guidance of [RFC6123].

5.1.  Control of Function through Configuration and Policy

   An implementation supporting this document SHOULD allow the operator
   to turn on and off the PCEP color capability advertisement
   (Section 3.1).  An implementation supporting this document SHOULD
   allow the configuration of color assignment to a TE Tunnel or an SR
   Policy.  A PCC MAY have a local policy configuration that specifies
   how the color tag is used.  This policy configuration is outside the
   scope of this document.

5.2.  Information and Data Models

   An implementation supporting this document SHOULD allow the inclusion
   of color in the data model used to retrieve the operational state of
   a TE tunnel or an SR policy.  The YANG model in
   [I-D.ietf-teas-yang-te] [YANG-TE] could be
   used to retrieve the operational state of a TE tunnel, and the YANG
   model in
   [I-D.ietf-spring-sr-policy-yang] [SR-POLICY-YANG] could be used to retrieve the operational
   state of an SR policy.

5.3.  Liveness Detection and Monitoring

   The extensions defined in this document do not require any additional
   liveness detection and monitoring support.  See [RFC5440] and
   [RFC5886] for more information.

5.4.  Verifying Correct Operation

   The operator MAY retrieve the operational state of TE Paths to verify
   if they are tagged with the correct intended color.

5.5.  Requirements on Other Protocols

   This document places no explicit requirements on other protocols.

5.6.  Impact on Network Operation

   The impact on network operations depends on how the color tag is used
   in the deployment.  This is outside the scope of this document.

6.  IANA Considerations

6.1.  PCEP TLV Type Indicator

   This document introduces

   IANA has assigned a value in the "PCEP TLV Type Indicators" registry
   of the "Path Computation Element Protocol (PCEP) Numbers" registry
   group as follows:

                    +=======+=============+===========+
                    | Value | Description | Reference
    ---------------------------------------------- |
                    +=======+=============+===========+
                    | 67    | Color                   This document

   Note: The code point specified for the TLV Type Indicator is an early
   allocation by IANA.       | RFC 9863  |
                    +-------+-------------+-----------+

                                  Table 1

6.2.  STATEFUL-PCE-CAPABILITY TLV Flag Field

   This document introduces

   IANA has assigned a bit value in the "STATEFUL-PCE-CAPABILITY TLV
   Flag Field" registry of the "Path Computation Element Protocol (PCEP)
   Numbers" registry group as follows:

                 +=======+==================+===========+
                 | Value | Description      | Reference
    ---------------------------------------------- |
                 +=======+==================+===========+
                 | 20    | COLOR-CAPABILITY        This document

   Note: The code point specified for the STATEFUL-PCE-CAPABILITY TLV
   Flag is an early allocation by IANA. | RFC 9863  |
                 +-------+------------------+-----------+

                                 Table 2

6.3.  PCEP-Error Object

   This document introduces

   IANA has assigned two Error-values for Error-Type=19 (Invalid
   Operation) within the "PCEP-ERROR Object Error Types and Values"
   registry of the "Path Computation Element Protocol (PCEP) Numbers"
   registry group as follows:

    Error-

    +============+===================+===================+===========+
    | Error-Type | Meaning           | Error-value       | Reference
    Type
    ------------------------------------------------------------------ |
    +============+===================+===================+===========+
    | 19         | Invalid Operation  TBD1: | 31: Invalid Color       This document
                               TBD2: | RFC 9863  |
    |            |                   +-------------------+-----------+
    |            |                   | 32: Inconsistent  | RFC 9863  |
    |            |                   | Color  This document             |           |
    +------------+-------------------+-------------------+-----------+

                                 Table 3

6.4.  LSP-ERROR-CODE TLV Error Code Field

   An earlier

   A draft version of this document added an error code in the "LSP-
   ERROR-CODE TLV Error Code Field" registry of the "Path Computation
   Element Protocol (PCEP) Numbers" registry group, which was also early
   allocated by the IANA.

   IANA is requested to cancel the early allocation made which is not
   needed anymore.  As per the instructions from the chairs, please mark has marked it as deprecated.

          +=======+================================+===========+
          | Value | Meaning                        | Reference
      ------------------------------------------------------ |
          +=======+================================+===========+
          | 9     | Deprecated (Unsupported Color)  This document

7.  Implementation Status

   [Note to the RFC Editor - remove this section before publication, as
   well as remove the reference to | RFC 7942.]

   This section records the status of known implementations of the
   protocol defined by this specification at the time of posting of this
   Internet-Draft, and is based on a proposal described in [RFC7942].
   The description of implementations in this section is intended to
   assist the IETF in its decision processes in progressing drafts to
   RFCs.  Please note that the listing of any individual implementation
   here does not imply endorsement by the IETF.  Furthermore, no effort
   has been spent to verify the information presented here that was
   supplied by IETF contributors.  This is not intended as, and must not
   be construed to be, a catalog of available implementations or their
   features.  Readers are advised to note that other implementations may
   exist.

   According to [RFC7942], "this will allow reviewers and working groups
   to assign due consideration to documents that have the benefit of
   running code, which may serve as evidence of valuable experimentation
   and feedback that have made the implemented protocols more mature.
   It is up to the individual working groups to use this information as
   they see fit".

   At the time of publication of this version, there are no known
   implementations.  Juniper Networks has plans to implement the
   extensions defined in this document.

8.  Acknowledgments

   The authors would like to thank Kaliraj Vairavakkalai, Colby Barth,
   Natrajan Venkataraman, Tarek Saad, Dhruv Dhody, Adrian Farrel, Andrew
   Stone, Diego Achaval, and Narasimha Kommuri for their review and
   suggestions.

9.  Contributors

   The following people have contributed to this document:

   Quan Xiong
   ZTE Corporation
   Email: xiong.quan@zte.com.cn

10. 9863  |
          +-------+--------------------------------+-----------+

                                 Table 4

7.  References

10.1.

7.1.  Normative References

   [I-D.ietf-pce-segment-routing-policy-cp]
              Koldychev, M., Sivabalan, S., Sidor, S., Barth, C., Peng,
              S., and H. Bidgoli, "Path Computation Element
              Communication Protocol (PCEP) Extensions for Segment
              Routing (SR) Policy Candidate Paths", Work in Progress,
              Internet-Draft, draft-ietf-pce-segment-routing-policy-cp-
              22, 25 February 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-pce-
              segment-routing-policy-cp-22>.

   [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>.

   [RFC5440]  Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
              Element (PCE) Communication Protocol (PCEP)", RFC 5440,
              DOI 10.17487/RFC5440, March 2009,
              <https://www.rfc-editor.org/info/rfc5440>.

   [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>.

   [RFC8231]  Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path
              Computation Element Communication Protocol (PCEP)
              Extensions for Stateful PCE", RFC 8231,
              DOI 10.17487/RFC8231, September 2017,
              <https://www.rfc-editor.org/info/rfc8231>.

   [RFC8253]  Lopez, D., Gonzalez de Dios, O., Wu, Q., and D. Dhody,
              "PCEPS: Usage of TLS to Provide a Secure Transport for the
              Path Computation Element Communication Protocol (PCEP)",
              RFC 8253, DOI 10.17487/RFC8253, October 2017,
              <https://www.rfc-editor.org/info/rfc8253>.

   [RFC8281]  Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "Path
              Computation Element Communication Protocol (PCEP)
              Extensions for PCE-Initiated LSP Setup in a Stateful PCE
              Model", RFC 8281, DOI 10.17487/RFC8281, December 2017,
              <https://www.rfc-editor.org/info/rfc8281>.

   [RFC8408]  Sivabalan, S., Tantsura, J., Minei, I., Varga, R., and J.
              Hardwick, "Conveying Path Setup Type in PCE Communication
              Protocol (PCEP) Messages", RFC 8408, DOI 10.17487/RFC8408,
              July 2018, <https://www.rfc-editor.org/info/rfc8408>.

   [RFC8664]  Sivabalan, S., Filsfils, C., Tantsura, J., Henderickx, W.,
              and J. Hardwick, "Path Computation Element Communication
              Protocol (PCEP) Extensions for Segment Routing", RFC 8664,
              DOI 10.17487/RFC8664, December 2019,
              <https://www.rfc-editor.org/info/rfc8664>.

   [RFC8745]  Ananthakrishnan, H., Sivabalan, S., Barth, C., Minei, I.,
              and M. Negi, "Path Computation Element Communication
              Protocol (PCEP) Extensions for Associating Working and
              Protection Label Switched Paths (LSPs) with Stateful PCE",
              RFC 8745, DOI 10.17487/RFC8745, March 2020,
              <https://www.rfc-editor.org/info/rfc8745>.

   [RFC9012]  Patel, K., Van de Velde, G., Sangli, S., and J. Scudder,
              "The BGP Tunnel Encapsulation Attribute", RFC 9012,
              DOI 10.17487/RFC9012, April 2021,
              <https://www.rfc-editor.org/info/rfc9012>.

   [RFC9325]  Sheffer, Y., Saint-Andre, P., and T. Fossati,
              "Recommendations for Secure Use of Transport Layer
              Security (TLS) and Datagram Transport Layer Security
              (DTLS)", BCP 195, RFC 9325, DOI 10.17487/RFC9325, November
              2022, <https://www.rfc-editor.org/info/rfc9325>.

10.2.  Informative References
   [I-D.ietf-spring-sr-policy-yang]
              Raza, S. K., Saleh, T., Shunwan, Z., Voyer, D., Durrani,

   [RFC9862]  Koldychev, M., Matsushima, Sivabalan, S., Sidor, S., Barth, C., Peng,
              S., and V. P. Beeram, "YANG Data Model H. Bidgoli, "Path Computation Element
              Communication Protocol (PCEP) Extensions for Segment
              Routing Policy", Work in Progress, Internet-Draft,
              draft-ietf-spring-sr-policy-yang-04, 22 November 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-spring-
              sr-policy-yang-04>.

   [I-D.ietf-teas-yang-te]
              Saad, T., Gandhi, R., Liu, X., Beeram, V. P., and I.
              Bryskin, "A YANG Data Model for Traffic Engineering
              Tunnels, Label Switched Paths and Interfaces", Work in
              Progress, Internet-Draft, draft-ietf-teas-yang-te-37, 9
              October 2024, <https://datatracker.ietf.org/doc/html/
              draft-ietf-teas-yang-te-37>. (SR) Policy Candidate Paths", RFC 9862,
              DOI 10.17487/RFC9862, September 2025,
              <https://www.rfc-editor.org/info/rfc9862>.

7.2.  Informative References

   [RFC3063]  Ohba, Y., Katsube, Y., Rosen, E., and P. Doolan, "MPLS
              Loop Prevention Mechanism", RFC 3063,
              DOI 10.17487/RFC3063, February 2001,
              <https://www.rfc-editor.org/info/rfc3063>.

   [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>.

   [RFC3630]  Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
              (TE) Extensions to OSPF Version 2", RFC 3630,
              DOI 10.17487/RFC3630, September 2003,
              <https://www.rfc-editor.org/info/rfc3630>.

   [RFC5305]  Li, T. and H. Smit, "IS-IS Extensions for Traffic
              Engineering", RFC 5305, DOI 10.17487/RFC5305, October
              2008, <https://www.rfc-editor.org/info/rfc5305>.

   [RFC5329]  Ishiguro, K., Manral, V., Davey, A., and A. Lindem, Ed.,
              "Traffic Engineering Extensions to OSPF Version 3",
              RFC 5329, DOI 10.17487/RFC5329, September 2008,
              <https://www.rfc-editor.org/info/rfc5329>.

   [RFC5886]  Vasseur, JP., Ed., Le Roux, JL., and Y. Ikejiri, "A Set of
              Monitoring Tools for Path Computation Element (PCE)-Based
              Architecture", RFC 5886, DOI 10.17487/RFC5886, June 2010,
              <https://www.rfc-editor.org/info/rfc5886>.

   [RFC6123]  Farrel, A., "Inclusion of Manageability Sections in Path
              Computation Element (PCE) Working Group Drafts", RFC 6123,
              DOI 10.17487/RFC6123, February 2011,
              <https://www.rfc-editor.org/info/rfc6123>.

   [RFC7308]  Osborne, E., "Extended Administrative Groups in MPLS
              Traffic Engineering (MPLS-TE)", RFC 7308,
              DOI 10.17487/RFC7308, July 2014,
              <https://www.rfc-editor.org/info/rfc7308>.

   [RFC7942]  Sheffer, Y. and A. Farrel, "Improving Awareness of Running
              Code: The Implementation Status Section", BCP 205,
              RFC 7942, DOI 10.17487/RFC7942, July 2016,
              <https://www.rfc-editor.org/info/rfc7942>.

   [RFC9256]  Filsfils, C., Talaulikar, K., Ed., Voyer, D., Bogdanov,
              A., and P. Mattes, "Segment Routing Policy Architecture",
              RFC 9256, DOI 10.17487/RFC9256, July 2022,
              <https://www.rfc-editor.org/info/rfc9256>.

   [SR-POLICY-YANG]
              Raza, S. K., Saleh, T., Zhuang, S., Voyer, D., Durrani,
              M., Matsushima, S., and V. P. Beeram, "YANG Data Model for
              Segment Routing Policy", Work in Progress, Internet-Draft,
              draft-ietf-spring-sr-policy-yang-05, 25 May 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-spring-
              sr-policy-yang-05>.

   [YANG-TE]  Saad, T., Gandhi, R., Liu, X., Beeram, V. P., and I.
              Bryskin, "A YANG Data Model for Traffic Engineering
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Acknowledgments

   The authors would like to thank Kaliraj Vairavakkalai, Colby Barth,
   Natrajan Venkataraman, Tarek Saad, Dhruv Dhody, Adrian Farrel, Andrew
   Stone, Diego Achaval, and Narasimha Kommuri for their review and
   suggestions.

Contributors

   The following people have contributed to this document:

   Quan Xiong
   ZTE Corporation
   Email: xiong.quan@zte.com.cn

Authors' Addresses

   Balaji Rajagopalan
   Juniper Networks
   Email: balajir@juniper.net

   Vishnu Pavan Beeram
   Juniper Networks
   Email: vbeeram@juniper.net

   Shaofu Peng
   ZTE Corporation
   Email: peng.shaofu@zte.com.cn

   Mike Koldychev
   Ciena Corporation
   Email: mkoldych@proton.me

   Gyan Mishra
   Verizon Communications Inc.
   Email: gyan.s.mishra@verizon.com