Skip to main content

LSP State Reporting Extensions in Path Computation Element Communication Protocol (PCEP)
draft-sidor-pce-lsp-state-reporting-extensions-06

Document Type Active Internet-Draft (individual)
Authors Samuel Sidor , Zafar Ali , Cheng Li , Mike Koldychev , Andrew Stone
Last updated 2026-03-02
RFC stream (None)
Intended RFC status (None)
Formats
Stream Stream state (No stream defined)
Consensus boilerplate Unknown
RFC Editor Note (None)
IESG IESG state I-D Exists
Telechat date (None)
Responsible AD (None)
Send notices to (None)
draft-sidor-pce-lsp-state-reporting-extensions-06
PCE Working Group                                               S. Sidor
Internet-Draft                                                    Z. Ali
Intended status: Standards Track                     Cisco Systems, Inc.
Expires: 3 September 2026                                          C. Li
                                                     Huawei Technologies
                                                            M. Koldychev
                                                       Ciena Corporation
                                                                A. Stone
                                                                   Nokia
                                                            2 March 2026

LSP State Reporting Extensions in Path Computation Element Communication
                            Protocol (PCEP)
           draft-sidor-pce-lsp-state-reporting-extensions-06

Abstract

   The Path Computation Element Communication Protocol (PCEP) is defined
   in multiple RFCs for enabling communication between Path Computation
   Elements (PCEs) and Path Computation Clients (PCCs).

   Although PCEP defines various Label Switched Path (LSP) identifiers,
   attributes, and constraints, there are operational attributes
   available on the PCC that can enhance path computation and improve
   the debugging experience, which are not currently supported in PCEP.

   This document defines extensions to PCEP to include:

   *  Support for explicit or dynamic path types
   *  Mechanisms to mark LSPs as eligible for use as transit LSPs

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

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents 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 3 September 2026.

Sidor, et al.           Expires 3 September 2026                [Page 1]
Internet-Draft         STATE-REPORTING-EXTENSIONS             March 2026

Copyright Notice

   Copyright (c) 2026 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components
   extracted from this document must include Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Protocol Extensions . . . . . . . . . . . . . . . . . . . . .   4
     3.1.  STATEFUL-PCE-CAPABILITY TLV . . . . . . . . . . . . . . .   4
     3.2.  LSP-EXTENDED-FLAG TLV . . . . . . . . . . . . . . . . . .   4
   4.  Operation . . . . . . . . . . . . . . . . . . . . . . . . . .   4
     4.1.  Explicit or Dynamic Path  . . . . . . . . . . . . . . . .   4
     4.2.  LSP Transit Eligibility . . . . . . . . . . . . . . . . .   6
   5.  Manageability Considerations  . . . . . . . . . . . . . . . .   8
     5.1.  Control of Function and Policy  . . . . . . . . . . . . .   8
     5.2.  Information and Data Models . . . . . . . . . . . . . . .   8
     5.3.  Verify Correct Operations . . . . . . . . . . . . . . . .   8
     5.4.  Impact on Network Operations  . . . . . . . . . . . . . .   8
   6.  Implementation Status . . . . . . . . . . . . . . . . . . . .   8
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
     8.1.  STATEFUL-PCE-CAPABILITY TLV Flag  . . . . . . . . . . . .   9
     8.2.  LSP-EXTENDED-FLAG TLV Flags . . . . . . . . . . . . . . .  10
     8.3.  PCEP Error Object Error Types and Values  . . . . . . . .  10
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  11
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  11
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  12
   Appendix A.  Acknowledgements . . . . . . . . . . . . . . . . . .  12
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  12

Sidor, et al.           Expires 3 September 2026                [Page 2]
Internet-Draft         STATE-REPORTING-EXTENSIONS             March 2026

1.  Introduction

   A Stateful Path Computation Element (PCE) maintains comprehensive
   information on the current network state, including computed Label
   Switched Paths (LSPs), reserved network resources, and the pending
   path computation requests.  This information is critical for
   computing paths for traffic-engineering LSPs and any associated or
   dependent LSPs.

   This document introduces the ability to encode information regarding
   whether a path included in an Explicit Route Object (ERO) was
   specified explicitly or was the result of dynamic path computation
   executed by a PCE or PCC.  Such information can aid debuggability and
   can be used by other PCEs in the network to avoid triggering
   unnecessary path computations for LSPs where it is not intended
   (e.g., PCE-initiated LSPs with an explicit path).

   Additionally, this document specifies a set of extensions to PCEP to
   enhance the accuracy of path computations by considering LSP transit
   eligibility, for example, as described in the case of LSP stitching
   in [I-D.ietf-pce-stateful-interdomain].

   The Explicit Path mechanism described in this document is applicable
   to all path setup types.  The Transit Eligible mechanism described in
   this document is applicable to LSPs that have an associated Binding
   Label/SID as defined in [RFC9604].

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.  Terminology

   The following terms are used in this document:

   *  Binding Label/SID: A Binding Segment Identifier (SID) or Binding
      Label associated with an SR Policy or SR-TE LSP, as defined in
      [RFC9604].
   *  CP: Candidate Path, one of the candidate paths of an SR Policy.
   *  ERO: Explicit Route Object.
   *  LSP: Label Switched Path.
   *  PCC: Path Computation Client.
   *  PCE: Path Computation Element.
   *  PCEP: Path Computation Element Protocol.

Sidor, et al.           Expires 3 September 2026                [Page 3]
Internet-Draft         STATE-REPORTING-EXTENSIONS             March 2026

   *  SL: Segment List, a sequence of segments describing a path through
      the network.
   *  Transit LSP: An LSP whose Binding Label/SID is used as a segment
      (hop) in the path computed for another LSP.  By referring to the
      Binding Label/SID of the Transit LSP as a single segment, the
      head-end of the outer LSP can steer traffic along the inner LSP's
      path without having to encode all of its individual hops.  This
      technique is used, for example, in inter-domain LSP stitching as
      described in [I-D.ietf-pce-stateful-interdomain].

3.  Protocol Extensions

3.1.  STATEFUL-PCE-CAPABILITY TLV

   New flags are defined for the STATEFUL-PCE-CAPABILITY TLV, originally
   defined in Section 5.4 of [RFC8231].

   *  T (TRANSIT-ELIGIBLE-CAPABILITY): If set, indicates that the PCEP
      peer supports the advertisement of the Transit Eligible flag in
      the LSP-EXTENDED-FLAG as described in Section 4.2.
   *  X (EXPLICIT-PATH-CAPABILITY): If set, indicates that the PCEP peer
      supports the advertisement of the Explicit flag in the LSP-
      EXTENDED-FLAG.

3.2.  LSP-EXTENDED-FLAG TLV

   New flags are introduced in the LSP-EXTENDED-FLAG TLV, which was
   initially defined in Section 3.1 of [RFC9357].

   *  X (Explicit): If set, indicates that the path encoded in the ERO
      is explicitly specified and not dynamically computed by the PCEP
      peer.
   *  T (Transit Eligible): If set, indicates that the Binding Label/SID
      [RFC9604] of the LSP can be used in paths computed for other LSPs.

4.  Operation

4.1.  Explicit or Dynamic Path

   The X flag in the LSP-EXTENDED-FLAG TLV MUST NOT be set unless the
   EXPLICIT-PATH-CAPABILITY is supported by both PCEP peers.

   If a PCEP peer receives the X flag set in the LSP-EXTENDED-FLAG TLV
   without having negotiated EXPLICIT-PATH-CAPABILITY, it MUST send a
   PCErr message with Error-Type 10 and Error-Value TBA5 (see
   Section 8.3) and MUST ignore the flag.

Sidor, et al.           Expires 3 September 2026                [Page 4]
Internet-Draft         STATE-REPORTING-EXTENSIONS             March 2026

   If the EXPLICIT-PATH-CAPABILITY is not advertised, the PCE
   implementation MAY use a local policy to determine the type of path.

   For instance, if an operator requests the creation of a PCE-initiated
   Candidate Path with an explicit path, then such a path will be
   encoded in the ERO object of the PCInitiate message sent to the PCC.
   If the delegation of such LSP is transferred to another PCE, the new
   PCE will not know whether the path of the LSP was computed
   dynamically or explicitly specified by the operator.

   Even if a similar problem does not exist for LSPs originated on the
   PCC, information about the type of path may be valuable for other
   purposes, such as debuggability.

   For PCC-initiated LSPs, the X flag value is initially set by the PCC
   in the PCRpt message, and the PCE MUST set the flag value in PCUpd
   messages for such LSPs based on the last reported state.

   For PCE-initiated LSPs, the X flag value is initially set by the PCE
   in the PCInitiate message but MAY be modified in subsequent PCUpd
   messages.  The PCC MUST set the flag value in PCRpt messages for such
   LSPs based on the value received from the last PCInitiate or PCUpd
   message.

   It is important to note that the Explicit/Dynamic path type is a
   path-level property indicating the origin of the path decision
   (operator-defined vs. algorithmically computed), while strict and
   loose subobjects are hop-level properties defined per ERO subobject
   in [RFC5440] that describe how precisely each individual hop must be
   followed.  Both explicitly specified and dynamically computed paths
   can contain a mix of strict and loose subobjects:

   *  For an Explicitly Specified Path (X flag set): An operator might
      define a path that explicitly specifies certain hops (strict) but
      allows the forwarding plane to select the exact route for other
      segments (loose).  For example, "go strictly through Router A,
      then loosely to Network B, then strictly through Router C."
   *  For a Dynamically Computed Path (X flag not set): A PCE, when
      computing a path, might generate an ERO that includes strict hops
      (e.g., to satisfy specific constraints like avoiding certain
      links) and loose hops (e.g., where flexibility is allowed to
      optimize for metrics like shortest path).

   The following example illustrates the distinction.  Consider the
   topology below:

Sidor, et al.           Expires 3 September 2026                [Page 5]
Internet-Draft         STATE-REPORTING-EXTENSIONS             March 2026

       +----+     +----+     +----+     +----+
       | R1 |-----| R2 |-----| R3 |-----| R4 |
       +----+     +----+  \  +----+     +----+
                           \                 |
                          +----+        +----+
                          | R5 |--------| R6 |
                          +----+        +----+

   An operator wishes to create an LSP from R1 to R4 and explicitly
   requires that traffic passes through R2 (e.g., for policy reasons).
   The operator does not prescribe the exact route beyond R2.  The
   resulting ERO would contain R2 as a strict subobject followed by R4
   as a loose subobject.  Because the overall path was defined by the
   operator, the X flag is set (Explicit Path), even though one of the
   hops is loose.  The forwarding plane may choose either R2->R3->R4 or
   R2->R5->R6->R4 to reach R4.

   By contrast, consider a PCE that computes a path R1->R2->R3->R4 using
   all strict subobjects to satisfy a specific bandwidth constraint.
   Because the path was computed algorithmically by the PCE, the X flag
   is not set (Dynamic Path), even though every hop is strict.

   This distinction is operationally significant: a downstream PCE that
   receives delegation for an LSP can use the X flag to determine
   whether it should attempt to recompute the path.  For a PCE-initiated
   LSP with X flag set, the PCE SHOULD NOT recompute the path unless
   explicitly instructed to do so, as the explicit path reflects
   operator intent.

   For LSPs with multiple Segment Lists (SLs) per Candidate Path (CP),
   the path type (explicit or dynamic) is advertised only once per
   Candidate Path.  Therefore, it is not possible to mix dynamic and
   explicit Segment Lists within a single Candidate Path.

4.2.  LSP Transit Eligibility

   The T flag in the LSP-EXTENDED-FLAG TLV MUST NOT be set unless the
   TRANSIT-ELIGIBLE-CAPABILITY is supported by both PCEP peers.

   If a PCEP peer receives the T flag set in the LSP-EXTENDED-FLAG TLV
   without having negotiated TRANSIT-ELIGIBLE-CAPABILITY, it MUST send a
   PCErr message with Error-Type 10 and Error-Value TBA6 (see
   Section 8.3) and MUST ignore the flag.

   If the TRANSIT-ELIGIBLE-CAPABILITY is not advertised, the PCE
   implementation MAY use a local policy to determine the value of the
   Transit Eligible flag.

Sidor, et al.           Expires 3 September 2026                [Page 6]
Internet-Draft         STATE-REPORTING-EXTENSIONS             March 2026

   For PCC-initiated LSPs, the T flag value is initially set by the PCC
   in the PCRpt message.  The PCE MUST set the flag value in PCUpd
   messages for these LSPs based on the last reported state.

   For PCE-initiated LSPs, the T flag value is initially set by the PCE
   in the PCInitiate message but MAY be modified in subsequent PCUpd
   messages.  The PCC MUST set the flag value in PCRpt messages for
   these LSPs based on the value received from the latest PCInitiate or
   PCUpd message.

   The following example illustrates the use of the T flag.  Consider an
   inter-domain topology where a PCE is responsible for computing an
   end-to-end LSP across two domains:

          Domain 1              Domain 2
     +-----------------+   +-----------------+
     |                 |   |                 |
     |  R1----R2----R3-+---+-R3----R4----R5  |
     |        |        |   |                 |
     |       R6        |   |                 |
     |                 |   |                 |
     +-----------------+   +-----------------+

     LSP_B: R1 -> R3  (Binding SID: BS1, T flag set)
     LSP_C: R3 -> R5  (Binding SID: BS2, T flag set)

   LSP_B is an intra-domain LSP within Domain 1, traversing R1->R2->R3,
   with a Binding SID BS1 assigned to it.  LSP_C is an intra-domain LSP
   within Domain 2, traversing R3->R4->R5, with a Binding SID BS2
   assigned to it.  Both LSP_B and LSP_C have the T flag set in their
   LSP-EXTENDED-FLAG TLV, indicating to the PCE that their respective
   Binding SIDs may be used as segments in paths computed for other
   LSPs.

   When an operator requests an end-to-end LSP_A from R1 to R5, the PCE
   can leverage the T flag information to construct the path.  Instead
   of computing a full explicit path enumerating every hop across both
   domains, the PCE can use BS1 and BS2 as single-hop segments in the
   ERO for LSP_A.  The resulting ERO for LSP_A would be: {BS1 (strict),
   BS2 (strict)}, stitching the two intra-domain LSPs together.  Without
   the T flag, the PCE would have no standardized way to know which LSPs
   have Binding SIDs available and are eligible for use in this manner,
   potentially leading to suboptimal path computation or requiring out-
   of-band coordination.

Sidor, et al.           Expires 3 September 2026                [Page 7]
Internet-Draft         STATE-REPORTING-EXTENSIONS             March 2026

5.  Manageability Considerations

   All manageability requirements and considerations listed in [RFC5440]
   and [RFC8231] apply to the PCEP extensions defined in this document.
   In addition, requirements and considerations listed in this section
   apply.

5.1.  Control of Function and Policy

   A PCE or PCC implementation MAY allow the capability of supporting
   PCEP extensions introduced in this document to be enabled or disabled
   as part of the global configuration.

5.2.  Information and Data Models

   An implementation SHOULD allow the operator to view the capability
   defined in this document.  It is expected that a future version of
   the PCEP YANG module [RFC9826] will be extended to include the
   capability introduced in Section 3.1 for the PCEP peer.

5.3.  Verify Correct Operations

   Operation verification requirements already listed in [RFC5440] and
   [RFC8231] are applicable to mechanisms defined in this document.

5.4.  Impact on Network Operations

   The mechanisms defined in [RFC5440] and [RFC8231] also apply to the
   PCEP extensions defined in this document.

6.  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.

Sidor, et al.           Expires 3 September 2026                [Page 8]
Internet-Draft         STATE-REPORTING-EXTENSIONS             March 2026

   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".

7.  Security Considerations

   The security considerations described in [RFC8231] and [RFC5440] are
   applicable to this document.

   The X (Explicit) flag defined in this document reveals operator
   intent regarding how a path was determined -- whether it was hand-
   crafted by an operator or dynamically computed.  In networks where
   this distinction is sensitive, an attacker with access to PCEP
   messages could use this information to infer network management
   policies.  The security mechanisms defined in [RFC5440] (TCP-AO) and
   [RFC8231] (PCEPS with TLS) are sufficient to protect the
   confidentiality and integrity of this information.

   The T (Transit Eligible) flag defined in this document indicates that
   the Binding Label/SID of an LSP may be used in paths computed for
   other LSPs (e.g., for LSP stitching).  A misconfigured or malicious
   node setting this flag without authorization could cause traffic to
   be steered through unintended paths, potentially leading to policy
   violations or routing loops.  Implementations SHOULD enforce
   capability negotiation as described in Section 4.2 and MAY apply
   local policies to restrict the use of LSPs for transit, regardless of
   the flag value.

   These extensions do not introduce any new authentication or
   encryption requirements beyond those already specified in [RFC5440]
   and [RFC8231].

8.  IANA Considerations

8.1.  STATEFUL-PCE-CAPABILITY TLV Flag

   IANA maintains a registry, named "STATEFUL-PCE-CAPABILITY TLV Flag
   Field", within the "Path Computation Element Protocol (PCEP) Numbers"
   registry group to manage the Flags field of the STATEFUL-PCE-
   CAPABILITY TLV.  The registration policy for this registry is
   Standards Action [RFC8126].  IANA is requested to make the following
   assignments:

Sidor, et al.           Expires 3 September 2026                [Page 9]
Internet-Draft         STATE-REPORTING-EXTENSIONS             March 2026

        +======+=================================+===============+
        | Bit  | Description                     | Reference     |
        +======+=================================+===============+
        | TBA1 | T (TRANSIT-ELIGIBLE-CAPABILITY) | This document |
        +------+---------------------------------+---------------+
        | TBA2 | X (EXPLICIT-PATH-CAPABILITY)    | This document |
        +------+---------------------------------+---------------+

                                 Table 1

8.2.  LSP-EXTENDED-FLAG TLV Flags

   IANA maintains a registry, named "LSP-EXTENDED-FLAG TLV Flag Field",
   within the "Path Computation Element Protocol (PCEP) Numbers"
   registry group to manage the Flags field of the LSP-EXTENDED-FLAG
   TLV.  The registration policy for this registry is Standards Action
   [RFC8126].  IANA is requested to make the following assignments:

              +======+======================+===============+
              | Bit  | Description          | Reference     |
              +======+======================+===============+
              | TBA3 | X (Explicit)         | This document |
              +------+----------------------+---------------+
              | TBA4 | T (Transit Eligible) | This document |
              +------+----------------------+---------------+

                                  Table 2

8.3.  PCEP Error Object Error Types and Values

   IANA maintains a registry, named "PCEP-ERROR Object Error Types and
   Values", within the "Path Computation Element Protocol (PCEP)
   Numbers" registry group.  The registration policy for this registry
   is IETF Review [RFC8126].  IANA is requested to make the following
   assignments under Error-Type 10 "Reception of an invalid object"
   [RFC5440]:

Sidor, et al.           Expires 3 September 2026               [Page 10]
Internet-Draft         STATE-REPORTING-EXTENSIONS             March 2026

   +============+=============+=============================+=========+
   | Error-Type | Error-Value | Description                 |Reference|
   +============+=============+=============================+=========+
   | 10         | TBA5        | X flag set in LSP-EXTENDED- |This     |
   |            |             | FLAG TLV without EXPLICIT-  |document |
   |            |             | PATH-CAPABILITY negotiated  |         |
   +------------+-------------+-----------------------------+---------+
   | 10         | TBA6        | T flag set in LSP-EXTENDED- |This     |
   |            |             | FLAG TLV without TRANSIT-   |document |
   |            |             | ELIGIBLE-CAPABILITY         |         |
   |            |             | negotiated                  |         |
   +------------+-------------+-----------------------------+---------+

                                 Table 3

9.  References

9.1.  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,
              <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>.

   [RFC8126]  Cotton, M., Leiba, B., and T. Narten, "Guidelines for
              Writing an IANA Considerations Section in RFCs", BCP 26,
              RFC 8126, DOI 10.17487/RFC8126, June 2017,
              <https://www.rfc-editor.org/info/rfc8126>.

   [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>.

   [RFC9357]  Xiong, Q., "Label Switched Path (LSP) Object Flag
              Extension for Stateful PCE", RFC 9357,
              DOI 10.17487/RFC9357, February 2023,
              <https://www.rfc-editor.org/info/rfc9357>.

Sidor, et al.           Expires 3 September 2026               [Page 11]
Internet-Draft         STATE-REPORTING-EXTENSIONS             March 2026

   [RFC9604]  Sivabalan, S., Filsfils, C., Tantsura, J., Previdi, S.,
              and C. Li, Ed., "Carrying Binding Label/SID in PCE-Based
              Networks", RFC 9604, DOI 10.17487/RFC9604, August 2024,
              <https://www.rfc-editor.org/info/rfc9604>.

9.2.  Informative References

   [I-D.ietf-pce-stateful-interdomain]
              Dugeon, O., Meuric, J., Lee, Y., and D. Ceccarelli, "PCEP
              Extension for Stateful Inter-Domain Tunnels", Work in
              Progress, Internet-Draft, draft-ietf-pce-stateful-
              interdomain-07, 3 March 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-pce-
              stateful-interdomain-07>.

   [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>.

   [RFC9826]  Dhody, D., Ed., Beeram, V., Hardwick, J., and J. Tantsura,
              "A YANG Data Model for the Path Computation Element
              Communication Protocol (PCEP)", RFC 9826,
              DOI 10.17487/RFC9826, September 2025,
              <https://www.rfc-editor.org/info/rfc9826>.

Appendix A.  Acknowledgements

   The authors would like to thank Rajesh Melarcode Venkateswaran for
   their contributions to this document.

Authors' Addresses

   Samuel Sidor
   Cisco Systems, Inc.
   Eurovea Central 3
   Pribinova 10
   811 09 Bratislava
   Slovakia
   Email: ssidor@cisco.com

   Zafar Ali
   Cisco Systems, Inc.
   Email: zali@cisco.com

Sidor, et al.           Expires 3 September 2026               [Page 12]
Internet-Draft         STATE-REPORTING-EXTENSIONS             March 2026

   Cheng Li
   Huawei Technologies
   Huawei Campus, No. 156 Beiqing Rd.
   Beijing
   100095
   China
   Email: c.l@huawei.com

   Mike Koldychev
   Ciena Corporation
   385 Terry Fox Dr.
   Kanata Ontario K2K 0L1
   Canada
   Email: mkoldych@proton.me

   Andrew Stone
   Nokia
   Email: andrew.stone@nokia.com

Sidor, et al.           Expires 3 September 2026               [Page 13]