Skip to main content

PCEP Operational Clarification
draft-ietf-pce-operational-02

Document Type Active Internet-Draft (pce WG)
Authors Mike Koldychev , Siva Sivabalan , Shuping Peng , Diego Achaval , Hari Kotni , Andrew Stone
Last updated 2025-12-22
Replaces draft-koldychev-pce-operational
RFC stream Internet Engineering Task Force (IETF)
Intended RFC status (None)
Formats
Additional resources Mailing list discussion
Stream WG state WG Document
Document shepherd (None)
IESG IESG state I-D Exists
Consensus boilerplate Unknown
Telechat date (None)
Responsible AD (None)
Send notices to (None)
draft-ietf-pce-operational-02
Path Computation Element                                    M. Koldychev
Internet-Draft                                              S. Sivabalan
Intended status: Informational                         Ciena Corporation
Expires: 25 June 2026                                            S. Peng
                                                     Huawei Technologies
                                                              D. Achaval
                                                                   Nokia
                                                                H. Kotni
                                                   Juniper Networks, Inc
                                                                A. Stone
                                                                   Nokia
                                                        22 December 2025

                     PCEP Operational Clarification
                     draft-ietf-pce-operational-02

Abstract

   This document clarifies certain operational behavior aspects of the
   PCEP protocol.  The content of this document has been compiled based
   on several interop exercises.

Discussion Venues

   This note is to be removed before publishing as an RFC.

   Discussion of this document takes place on the Path Computation
   Element mailing list (pce@ietf.org), which is archived at
   https://mailarchive.ietf.org/arch/browse/pce/.

   Source for this draft and an issue tracker can be found at
   https://github.com/ietf-wg-pce/draft-ietf-pce-operational.

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."

Koldychev, et al.         Expires 25 June 2026                  [Page 1]
Internet-Draft              PCEP-OPERATIONAL               December 2025

   This Internet-Draft will expire on 25 June 2026.

Copyright Notice

   Copyright (c) 2025 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  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . .   3
   3.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  PCEP LSP Database . . . . . . . . . . . . . . . . . . . . . .   4
     4.1.  Structure . . . . . . . . . . . . . . . . . . . . . . . .   4
     4.2.  Synchronization . . . . . . . . . . . . . . . . . . . . .   5
     4.3.  Make before Break (MBB) . . . . . . . . . . . . . . . . .   6
       4.3.1.  Successful MBB  . . . . . . . . . . . . . . . . . . .   6
       4.3.2.  Aborted MBB . . . . . . . . . . . . . . . . . . . . .   7
   5.  PCEP Association Database . . . . . . . . . . . . . . . . . .   8
     5.1.  LSPs in same Association  . . . . . . . . . . . . . . . .   8
     5.2.  Switch Association during MBB . . . . . . . . . . . . . .   9
   6.  Computation Constraints . . . . . . . . . . . . . . . . . . .  11
   7.  Overloaded PCE  . . . . . . . . . . . . . . . . . . . . . . .  11
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  12
   9.  Managability Considerations . . . . . . . . . . . . . . . . .  12
   10. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  12
   11. Normative References  . . . . . . . . . . . . . . . . . . . .  12
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .  12
   Contributors  . . . . . . . . . . . . . . . . . . . . . . . . . .  12
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  13

1.  Introduction

   Due to different interpretations of PCEP standards, it was found that
   implementations often had to adjust their behavior in order to
   interoperate.  The current document serves to clarify certain aspects
   of PCEP to make it easier to produce interoperable implementations of
   PCEP.

Koldychev, et al.         Expires 25 June 2026                  [Page 2]
Internet-Draft              PCEP-OPERATIONAL               December 2025

2.  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.

3.  Terminology

   The following terminologies are used in this document:

   PCC: Path Computation Client.  Any client application requesting a
   path computation to be performed by a Path Computation Element.

   PCE: Path Computation Element.  An entity (component, application, or
   network node) that is capable of computing a network path or route
   based on a network graph and applying computational constraints.

   PCEP: Path Computation Element Protocol.

   MBB: Make-Before-Break.  A procedure during which the head-end of a
   traffic-engineered path wishes to move traffic to a new path without
   losing any traffic, by first "making" a new path and then "breaking"
   the old path.

   Association parameters: As described in [RFC8697], the combination of
   the mandatory fields Association type, Association ID and Association
   Source in the ASSOCIATION object uniquely identify the association
   group.  If the optional TLVs - Global Association Source or Extended
   Association ID are included, then they are included in combination
   with mandatory fields to uniquely identify the association group.

   Association information: As described in [RFC8697], the ASSOCIATION
   object could also include other optional TLVs based on the
   association types, that provides 'information' related to the
   association type.

   ERO: Explicit Route Object is the path of the LSP encoded into a PCEP
   object.  In this document, an empty ERO object, i.e., without any
   subobjects, is represented with notation "ERO={}".  An ERO object
   containing a given sequence of subobjects is represented as
   "ERO={A}".

Koldychev, et al.         Expires 25 June 2026                  [Page 3]
Internet-Draft              PCEP-OPERATIONAL               December 2025

   PCRPT-LSP-DB: PCEP Reported Label Switched Path Database.  A logical
   datastore that captures the reported state information of Label
   Switched Paths (LSPs) within a PCEP speaker.  This term is not
   defined in the PCE architecture; however, it is used in this document
   to describe how a PCEP speaker internally maintains LSP-related state
   information reported via PCRpt messages.

   EXTENDED-LSP-DB: Extended Label Switched Path Database.  An
   implementation-specific logical datastore used to capture information
   related to a Label Switched Path.  It may be keyed using the same
   identifiers as the PCRPT-LSP-DB.  This term is not defined in the PCE
   architecture; however is used in this document to refer to a
   conceptual datastore that can include additional attributes—such as
   desired state, telemetry data, and other information not defined
   within IETF PCE working group documents.

   PLSP-ID (Path LSP Identifier): Introduced in [RFC8231].  A unique
   identifier used in PCEP to distinguish a specific LSP between a PCC
   and a PCE which is constant for the lifetime of a PCEP session.

4.  PCEP LSP Database

   This document uses the concept of the PCRPT-LSP-DB, a database of
   actual LSP state in the network, to illustrate the internal state of
   PCEP speakers in response to PcRpt messages.

   Note that the term "LSP", which stands for "Label Switched Path", if
   taken too literally, would restrict the discussion to the MPLS
   dataplane only.  In this document, the term "LSP" is applied to non-
   MPLS paths as well, to avoid renaming the term.  Alternatively, the
   term "LSP" could be replaced with "Instance".

4.1.  Structure

   The distinction between Tunnels and LSPs in the PCRPT-LSP-DB is
   essential for accurately modeling state information in PCEP,
   including procedures such as make-before-break, and for maintaining
   consistent state management across PCEP speakers.

   The PCRPT-LSP-DB contains two types of information: LSPs and Tunnels.
   An LSP is identified by the LSP-IDENTIFIERS TLV, while a Tunnel is
   identified by the PLSP-ID in the LSP object and/or the SYMBOLIC-NAME
   (see [RFC8231]).

   A Tunnel may or may not correspond to an actual tunnel on the router.
   For example, working and protect paths can be implemented as a single
   tunnel interface, but in PCEP, these are represented as two different
   Tunnels with different PLSP-IDs.

Koldychev, et al.         Expires 25 June 2026                  [Page 4]
Internet-Draft              PCEP-OPERATIONAL               December 2025

   An LSP can be viewed as an instance of a Tunnel.  In steady state, a
   Tunnel typically has a single LSP; however, during make-before-break
   procedures (see [RFC3209]), multiple LSPs may exist simultaneously to
   represent both the new and old instances during the transition.

4.2.  Synchronization

   Since the PCRPT-LSP-DB contains PCEP-specific information such as
   PLSP-IDs, which remain constant for the duration of a PCEP session,
   both the PCE and PCC maintain their own local copies of the PCRPT-
   LSP-DB.  The PCE PCRPT-LSP-DB is only modified by PCRpt messages, no
   other PCEP message may modify the PCE PCRPT-LSP-DB.  The PCC PCRPT-
   LSP-DB is built from actual forwarding state that PCC has installed.
   PCC uses PCRpt messages to synchronize its local PCRPT-LSP-DB to the
   PCE.

   The PCE is intended to act based on the most recent state available
   in the PCRPT-LSP-DB, which represents the actual state of Label
   Switched Paths (LSPs) in the network.  This does not preclude the PCE
   from leveraging information obtained outside the PCRPT-LSP-DB.  For
   example, implementation-specific mechanisms may be used to collect
   traffic statistics that can be considered during path computation.
   Such information is not part of the PCRPT-LSP-DB itself, but may
   reference it.  Additional data such as desired state, telemetry, or
   operator-intended configurations—may be maintained in a separate,
   implementation-specific logical datastore referred to as the
   EXTENDED-LSP-DB.

   Both the PCE and PCC maintain a PCRPT-LSP-DB that reflects the
   reported (actual) state of LSPs.  Implementations may choose to store
   desired state information or other attributes in the EXTENDED-LSP-DB.
   It is important to note that the PCRPT-LSP-DB reflects only the live
   view of the network and does not imply alignment with the desired
   state.

   For example, in the case of a PCE-initiated LSP, a change in the LSP
   configuration made by an operator represents a modification to the
   desired state.  However, the actual state does not change until the
   PCE sends a PCInit or PCUpd message to the PCC.  Upon receipt of such
   a message, the PCC may act on the request, update its local PCRPT-
   LSP-DB, and generate a PCRpt message to inform the PCE of the change.
   The PCE then updates its own PCRPT-LSP-DB accordingly.  Once this
   exchange is complete, the PCRPT-LSP-DBs on both the PCC and the PCE
   are synchronized.

Koldychev, et al.         Expires 25 June 2026                  [Page 5]
Internet-Draft              PCEP-OPERATIONAL               December 2025

4.3.  Make before Break (MBB)

   Due to variations in how different implementations interpret or
   handle MBB procedures—sometimes resulting in incorrect message
   processing or misinterpretation—the following section provides
   illustrative examples to clarify expected MBB behavior.

4.3.1.  Successful MBB

   Below is an example of performing MBB to switch a Tunnel from one
   path to another.  The path encoded into the ERO object is represented
   as ERO={A} and ERO={B}.

   PCC has an existing LSP in UP state, with LSP-ID=2.  PCC sends
   PCRpt(R-FLAG=0, PLSP-ID=100, LSP-ID=2, ERO={A}, OPER-FLAG=UP).

   +---------------------------------------------------------------+
   | TUNNEL          | LSP                                         |
   +-----------------+---------------------------------------------+
   | PLSP-ID=100     | LSP-ID=2, ERO={A}, OPER=UP                  |
   +---------------------------------------------------------------+

                   Figure 1: Content of LSP DB

   PCC initiates the MBB procedure by creating a new LSP with LSP-ID=3.
   It does not matter what triggered the creation of the new LSP, it
   could have been due to a new path received via PCUpd (if the given
   Tunnel is delegated), or it could have been local computation on the
   PCC (if the Tunnel is locally computed on the PCC), or it could have
   been a change in configuration on the PCC (if the Tunnel's path is
   explicitly configured on the PCC).  It is important to emphasize that
   the procedure for updating the PCRPT-LSP-DB is common, regardless of
   the trigger that caused the change.

   PCC sends PCRpt(R-FLAG=0, PLSP-ID=100, LSP-ID=3, ERO={B}, OPER-
   FLAG=UP).

   +---------------------------------------------------------------+
   | TUNNEL          | LSP                                         |
   +-----------------+---------------------------------------------+
   | PLSP-ID=100     | LSP-ID=2, ERO={A}, OPER=UP                  |
   |                 | LSP-ID=3, ERO={B}, OPER=UP                  |
   +---------------------------------------------------------------+

                   Figure 2: Content of LSP DB

Koldychev, et al.         Expires 25 June 2026                  [Page 6]
Internet-Draft              PCEP-OPERATIONAL               December 2025

   After traffic has successfully switched to the new LSP, the PCC
   cleans up the old LSP.  PCC sends PCRpt(R-FLAG=1, PLSP-ID=100, LSP-
   ID=2).

   +---------------------------------------------------------------+
   | TUNNEL          | LSP                                         |
   +-----------------+---------------------------------------------+
   | PLSP-ID=100     | LSP-ID=3, ERO={B}, OPER=UP                  |
   +---------------------------------------------------------------+

                   Figure 3: Content of LSP DB

4.3.2.  Aborted MBB

   The MBB process can abort when the newly created LSP is destroyed
   before it is installed as traffic carrying.  This scenario is
   described below.

   PCC has an existing LSP in UP state, with LSP-ID=2.  PCC sends
   PCRpt(R-FLAG=0, OPER-FLAG=UP, PLSP-ID=100, LSP-ID=2).

   +---------------------------------------------------------------+
   | TUNNEL          | LSP                                         |
   +-----------------+---------------------------------------------+
   | PLSP-ID=100     | LSP-ID=2, OPER=UP                           |
   +---------------------------------------------------------------+

                   Figure 4: Content of LSP DB

   MBB procedure is initiated, a new LSP is created with LSP-ID=3.  LSP
   is currently being established, so its oper state is DOWN.  PCC sends
   PCRpt(R-FLAG=0, OPER-FLAG=DOWN, PLSP-ID=100, LSP-ID=3).

   +---------------------------------------------------------------+
   | TUNNEL          | LSP                                         |
   +-----------------+---------------------------------------------+
   | PLSP-ID=100     | LSP-ID=2, OPER=UP                           |
   |                 | LSP-ID=3, OPER=DOWN                         |
   +---------------------------------------------------------------+

                   Figure 5: Content of LSP DB

   MBB procedure is aborted.  PCC sends PCRpt(R-FLAG=1, PLSP-ID=100,
   LSP-ID=3).

Koldychev, et al.         Expires 25 June 2026                  [Page 7]
Internet-Draft              PCEP-OPERATIONAL               December 2025

   +---------------------------------------------------------------+
   | TUNNEL          | LSP                                         |
   +-----------------+---------------------------------------------+
   | PLSP-ID=100     | LSP-ID=2, OPER=UP                           |
   +---------------------------------------------------------------+

                   Figure 6: Content of LSP DB

5.  PCEP Association Database

   PCEP Association is the instantiate of a group containing at least
   one LSP.

   The PCE ASSO DB is populated by PCRpt messages and/or via
   configuration on the PCE itself.  An Association is identified by the
   Association Parameters.  As the Association Parameters contain many
   fields, all fields are grouped into a single value for convenience.
   The notation ASSO_PARAM=A and ASSO_PARAM=B is used to refer to
   different PCEP Associations: A and B, respectively.

5.1.  LSPs in same Association

   The following example illustrates how LSPs join the same Association.

   PCC creates the first LSP.  PCC sends PCRpt(R-FLAG=0, PLSP-ID=100,
   LSP-ID=1, ASSO_PARAM=A, ASSO_R_FLAG=0).

   +---------------------------------------------------------------+
   | ASSO            | LSP                                         |
   +-----------------+---------------------------------------------+
   | ASSO_PARAM=A    | PLSP-ID=100, LSP-ID=1                       |
   +---------------------------------------------------------------+

                   Figure 7: Content of PCE ASSO DB

   PCC creates the second LSP.  PCC sends PCRpt(R-FLAG=0, PLSP-ID=200,
   LSP-ID=1, ASSO_PARAM=A, ASSO_R_FLAG=0).

   +---------------------------------------------------------------+
   | ASSO            | LSP                                         |
   +-----------------+---------------------------------------------+
   | ASSO_PARAM=A    | PLSP-ID=100, LSP-ID=1                       |
   |                 | PLSP-ID=200, LSP-ID=1                       |
   +---------------------------------------------------------------+

                   Figure 8: Content of PCE ASSO DB

Koldychev, et al.         Expires 25 June 2026                  [Page 8]
Internet-Draft              PCEP-OPERATIONAL               December 2025

   PCC updates the first LSP.  As [RFC8697] indicates, subsequent PcRpt
   should include only the associations that are being modified or
   removed.  Therefore it is optional as to send the ASSOCIATION object
   in this PCRpt, since the LSP is already in the Association.  PCC
   sends PCRpt(R-FLAG=0, PLSP-ID=100, LSP-ID=1).  The content of the PCE
   ASSO DB is unchanged.  Note that the PCC sends the ASSOCIATION OBJECT
   in the first PCRpt during SYNC state, even if it has already issued a
   PCRpt with the association object sometime in the past with this PCE.
   The synchronization steps outlined in [RFC8697] are to be followed.

   +---------------------------------------------------------------+
   | ASSO            | LSP                                         |
   +-----------------+---------------------------------------------+
   | ASSO_PARAM=A    | PLSP-ID=100, LSP-ID=1                       |
   |                 | PLSP-ID=200, LSP-ID=1                       |
   +---------------------------------------------------------------+

                   Figure 9: Content of PCE ASSO DB

   PCC decides to delete the second LSP.  PCC sends PCRpt(R-FLAG=1,
   PLSP-ID=200, LSP-ID=1).

   +---------------------------------------------------------------+
   | ASSO            | LSP                                         |
   +-----------------+---------------------------------------------+
   | ASSO_PARAM=A    | PLSP-ID=100, LSP-ID=1                       |
   +---------------------------------------------------------------+

                   Figure 10: Content of PCE ASSO DB

   PCC decides to remove the first LSP from the Association, but not
   delete the LSP itself.  PCC sends PCRpt(R-FLAG=0, PLSP-ID=100, LSP-
   ID=1, ASSO_PARAM=A, ASSO_R_FLAG=1).  The PCE ASSO DB is now empty.

   +---------------------------------------------------------------+
   | ASSO            | LSP                                         |
   +-----------------+---------------------------------------------+
   | -               |                                             |
   +---------------------------------------------------------------+

                   Figure 11: Content of PCE ASSO DB

5.2.  Switch Association during MBB

   The following example illustrates how a Tunnel goes through MBB and
   switches from Association A to Association B.

Koldychev, et al.         Expires 25 June 2026                  [Page 9]
Internet-Draft              PCEP-OPERATIONAL               December 2025

   Each new LSP (identified by the LSP-ID) does not inherit the
   Association membership of any previous LSPs within the same Tunnel.
   This is so that a Tunnel can have two LSPs that are in different
   Associations, this may be done when switching from one Association to
   another.

   PCC creates the first LSP.  PCC sends PCRpt(R-FLAG=0, PLSP-ID=100,
   LSP-ID=1, ASSO_PARAM=A, ASSO_R_FLAG=0).

   +---------------------------------------------------------------+
   | ASSO            | LSP                                         |
   +-----------------+---------------------------------------------+
   | ASSO_PARAM=A    | PLSP-ID=100, LSP-ID=1                       |
   +---------------------------------------------------------------+

                   Figure 12: Content of PCE ASSO DB

   PCC creates the MBB LSP in a different Association.  PCC sends
   PCRpt(R-FLAG=0, PLSP-ID=100, LSP-ID=2, ASSO_PARAM=B, ASSO_R_FLAG=0).

   +---------------------------------------------------------------+
   | ASSO            | LSP                                         |
   +-----------------+---------------------------------------------+
   | ASSO_PARAM=A    | PLSP-ID=100, LSP-ID=1                       |
   +---------------------------------------------------------------+
   | ASSO_PARAM=B    | PLSP-ID=100, LSP-ID=2                       |
   +---------------------------------------------------------------+

                   Figure 13: Content of PCE ASSO DB

   PCC deletes the old LSP.  PCC sends PCRpt(R-FLAG=1, PLSP-ID=100, LSP-
   ID=1).

   +---------------------------------------------------------------+
   | ASSO            | LSP                                         |
   +-----------------+---------------------------------------------+
   | ASSO_PARAM=B    | PLSP-ID=100, LSP-ID=2                       |
   +---------------------------------------------------------------+

                   Figure 14: Content of PCE ASSO DB

Koldychev, et al.         Expires 25 June 2026                 [Page 10]
Internet-Draft              PCEP-OPERATIONAL               December 2025

6.  Computation Constraints

   As well as reporting any state change in the network on a PCRpt
   message, a PCC may also change the parameters of a delegated LSP.
   For example, it may remove or modify the computation constraints that
   it wishes the PCE to apply as it computes any updated paths in the
   future.  For any PCEP object that specifies a path computation
   constraint and that does not have a defined explicit removal flag,
   the absence of that entire object on a repeat or follow-up PcRpt
   message indicates removal of the constraint previously specified by
   that object.  For example, suppose the first PcRpt contains an LSPA
   object with some affinity constraints.  Then if a subsequent PcRpt
   does not contain an LSPA object, then this means that the previously
   specified affinity constraints do not apply anymore.  Same applies to
   all PCEP objects, like METRIC, BANDWIDTH, etc., which do not have an
   explicit flag for removal.  This simply ensures that it is possible
   to remove a constraint without using an explicit removal flag.

7.  Overloaded PCE

   [RFC5440] defines the concept of an Overloaded PCE and explains how a
   PCE may signal to a PCC that it is congested, instructing that "no
   requests should be sent to that PCE until the overload state is
   cleared."

   In the case of an overloaded PCE, a PCC implementation could choose
   to wait for the PCE to no longer be overloaded or instead send a
   PcReq to a backup, non-overloaded PCE instead.

   [RFC8231] builds upon [RFC5440] by introducing the concept of a
   Stateful PCE, which allows delegation of LSP control to a single PCE.
   However, it does not address the case of an overloaded PCE.
   According to [RFC8231], a PCE maintains delegation until it is
   revoked by the PCC or returned back to PCC by the PCE.  The PCC may
   revoke delegation and re-assign it to another PCE.

   As a result, a PCE in an overload state still retains LSP delegation.
   For PCC-initiated LSPs, the PCC may revoke delegation from the
   overloaded PCE and maintain delegation for itself or delegate it to
   another PCE.  For PCE-initiated LSPs, since the PCC cannot revoke
   delegation as per [RFC8281], the overloaded PCE may return the
   delegation to the PCC.

   The PCE will continue to send PcRpt messages to PCE even though it
   may indicate it is overloaded, otherwise the the PCRPT-LSP-DB on PCE
   may go out of sync.

Koldychev, et al.         Expires 25 June 2026                 [Page 11]
Internet-Draft              PCEP-OPERATIONAL               December 2025

8.  Security Considerations

   None at this time.

9.  Managability Considerations

   None at this time.

10.  IANA Considerations

   None at this time.

11.  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/rfc/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/rfc/rfc3209>.

   [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/rfc/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/rfc/rfc8231>.

   [RFC8697]  Minei, I., Crabbe, E., Sivabalan, S., Ananthakrishnan, H.,
              Dhody, D., and Y. Tanaka, "Path Computation Element
              Communication Protocol (PCEP) Extensions for Establishing
              Relationships between Sets of Label Switched Paths
              (LSPs)", RFC 8697, DOI 10.17487/RFC8697, January 2020,
              <https://www.rfc-editor.org/rfc/rfc8697>.

Acknowledgments

   The authors would like to thank Adrian Farrel and Tom Petch for
   useful review and feedback. comments.

Contributors

Koldychev, et al.         Expires 25 June 2026                 [Page 12]
Internet-Draft              PCEP-OPERATIONAL               December 2025

   Dhruv Dhody
   Huawei Technologies
   Email: dhruv.ietf@gmail.com

   Samuel Sidor
   Cisco Systems
   Email: ssidor@cisco.com

   Mahendra Singh Negi
   RtBrick Inc
   Email: mahend.ietf@gmail.com

Authors' Addresses

   Mike Koldychev
   Ciena Corporation
   Email: mkoldych@proton.me

   Siva Sivabalan
   Ciena Corporation
   Email: ssivabal@ciena.com

   Shuping Peng
   Huawei Technologies
   Email: pengshuping@huawei.com

   Diego Achaval
   Nokia
   Email: diego.achaval@nokia.com

   Hari Kotni
   Juniper Networks, Inc
   Email: hkotni@juniper.net

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

Koldychev, et al.         Expires 25 June 2026                 [Page 13]