Conveying Vendor-Specific Information in the Path Computation Element (PCE) Communication Protocol (PCEP) extensions for Stateful PCE.
draft-ietf-pce-stateful-pce-vendor-02

PCE Working Group                                                  C. Li
Internet-Draft                                                  H. Zheng
Intended status: Standards Track                     Huawei Technologies
Expires: 8 August 2024                                      S. Sivabalan
                                                                   Ciena
                                                                S. Sidor
                                                                  Z. Ali
                                                     Cisco Systems, Inc.
                                                         5 February 2024

 Conveying Vendor-Specific Information in the Path Computation Element
    (PCE) Communication Protocol (PCEP) extensions for Stateful PCE.
                 draft-ietf-pce-stateful-pce-vendor-02

Abstract

   A Stateful Path Computation Element (PCE) maintains information on
   the current network state, including computed Label Switched Path
   (LSPs), reserved resources within the network, and the pending path
   computation requests.  This information may then be considered when
   computing new traffic engineered LSPs, and for the associated and the
   dependent LSPs, received from a Path Computation Client (PCC).

   RFC 7470 defines a facility to carry vendor-specific information in
   stateless Path Computation Element Communication Protocol (PCEP).

   This document extends this capability for the Stateful PCEP messages.

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
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   Drafts is at https://datatracker.ietf.org/drafts/current/.

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   This Internet-Draft will expire on 8 August 2024.

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Copyright Notice

   Copyright (c) 2024 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   Please review these documents carefully, as they describe your rights
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  Procedures for the Vendor Information Object  . . . . . . . .   3
   3.  Procedures for the Vendor Information TLV . . . . . . . . . .   6
   4.  Vendor Information Object and TLV . . . . . . . . . . . . . .   6
   5.  Manageability Considerations  . . . . . . . . . . . . . . . .   7
     5.1.  Control of Function and Policy  . . . . . . . . . . . . .   7
     5.2.  Information and Data Models . . . . . . . . . . . . . . .   7
     5.3.  Liveness Detection and Monitoring . . . . . . . . . . . .   7
     5.4.  Verify Correct Operations . . . . . . . . . . . . . . . .   7
     5.5.  Requirements On Other Protocols . . . . . . . . . . . . .   7
     5.6.  Impact On Network Operations  . . . . . . . . . . . . . .   7
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
   7.  Implementation Status . . . . . . . . . . . . . . . . . . . .   8
     7.1.  Cisco Systems . . . . . . . . . . . . . . . . . . . . . .   8
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
   9.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   9
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     10.1.  Normative References . . . . . . . . . . . . . . . . . .   9
     10.2.  Informative References . . . . . . . . . . . . . . . . .  10
   Appendix A.  Contributor Addresses  . . . . . . . . . . . . . . .  11
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  11

1.  Introduction

   The Path Computation Element Communication Protocol (PCEP) [RFC5440]
   provides mechanisms for a Path Computation Element (PCE) to perform
   path computation in response to a Path Computation Client (PCC)
   request.

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   A Stateful PCE is capable of considering, for the purposes of the
   path computation, not only the network state in terms of links and
   nodes (referred to as the Traffic Engineering Database or TED) but
   also the status of active services (previously computed paths, and
   currently reserved resources, stored in the Label Switched Paths
   Database (LSP-DB).  [RFC8051] describes general considerations for a
   Stateful PCE deployment and examines its applicability and benefits,
   as well as its challenges and limitations through a number of use
   cases.

   [RFC8231] describes a set of extensions to PCEP to provide stateful
   control.  A Stateful PCE has access to not only the information
   carried by the network's Interior Gateway Protocol (IGP), but also
   the set of active paths and their reserved resources for its
   computations.  The additional state allows the PCE to compute
   constrained paths while considering individual LSPs and their
   interactions.  [RFC8281] describes the setup, maintenance, and
   teardown of PCE-initiated LSPs under the Stateful PCE model.  These
   extensions added new messages in PCEP for Stateful PCE.

   [RFC7470] defined Vendor Information object that can be used to carry
   arbitrary, proprietary information such as vendor-specific
   constraints in stateless PCEP.  It also defined VENDOR-INFORMATION-
   TLV that can be used to carry arbitrary information within any
   existing or future PCEP object that supports TLVs.

   This document extends the usage of Vendor Information Object and
   VENDOR-INFORMATION-TLV to Stateful PCE.  The VENDOR-INFORMATION-TLV
   can be carried inside any of the new objects added in PCEP for
   Stateful PCE as per [RFC7470], this document extends the stateful
   PCEP messages to also include the Vendor Information Object as well.

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.  Procedures for the Vendor Information Object

   A Path Computation LSP State Report message (also referred to as
   PCRpt message) [RFC8231] is a PCEP message sent by a PCC to a PCE to
   report the current state of an LSP.  A PCC that wants to convey
   proprietary or vendor-specific information or metrics to a PCE does
   so by including a Vendor Information object in the PCRpt message.
   The contents and format of the object are described in Section 4 of

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   [RFC7470].  The PCE determines how to interpret the information in
   the Vendor Information object by examining the Enterprise Number it
   contains.

   The Vendor Information object is OPTIONAL in a PCRpt message.
   Multiple instances of the object MAY be used on a single PCRpt
   message.  Different instances of the object can have different
   Enterprise Numbers.

   The format of the PCRpt message (with [RFC8231] as base) is updated
   as follows:

         <PCRpt Message> ::= <Common Header>
                             <state-report-list>
      Where:

         <state-report-list> ::= <state-report>[<state-report-list>]

         <state-report> ::= [<SRP>]
                            <LSP>
                            <path>
                            [<vendor-info-list>]
       Where:
         <vendor-info-list> ::= <VENDOR-INFORMATION>
                                [<vendor-info-list>]

         <path> is defined in [RFC8231].

   A Path Computation LSP Update Request message (also referred to as
   PCUpd message) [RFC8231] is a PCEP message sent by a PCE to a PCC to
   update attributes of an LSP.  The Vendor Information object can be
   included in a PCUpd message to convey proprietary or vendor-specific
   information.

   The format of the PCUpd message (with [RFC8231] as base) is updated
   as follows:

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         <PCUpd Message> ::= <Common Header>
                             <update-request-list>
      Where:

         <update-request-list> ::= <update-request>
                             [<update-request-list>]

         <update-request> ::= <SRP>
                              <LSP>
                              <path>
                              [<vendor-info-list>]
      Where:
         <vendor-info-list> ::= <VENDOR-INFORMATION>
                                [<vendor-info-list>]

         <path> is defined in [RFC8231].

   A Path Computation LSP Initiate Message (also referred to as
   PCInitiate message) [RFC8281] is a PCEP message sent by a PCE to a
   PCC to trigger an LSP instantiation or deletion.  The Vendor
   Information object can be included in a PCInitiate message to convey
   proprietary or vendor-specific information.

   The format of the PCInitiate message (with [RFC8281] as base) is
   updated as follows:

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        <PCInitiate Message> ::= <Common Header>
                                 <PCE-initiated-lsp-list>
     Where:

        <PCE-initiated-lsp-list> ::= <PCE-initiated-lsp-request>
                                     [<PCE-initiated-lsp-list>]

        <PCE-initiated-lsp-request> ::=
                             (<PCE-initiated-lsp-instantiation>|
                              <PCE-initiated-lsp-deletion>)

        <PCE-initiated-lsp-instantiation> ::= <SRP>
                                              <LSP>
                                              [<END-POINTS>]
                                              <ERO>
                                              [<attribute-list>]
                                              [<vendor-info-list>]

        Where:

        <vendor-info-list> ::= <VENDOR-INFORMATION>
                               [<vendor-info-list>]

        <PCE-initiated-lsp-deletion> and <attribute-list> is as per
        [RFC8281].

   A legacy implementation that does not recognize the Vendor
   Information object will act according to the procedures set out in
   [RFC8231] and [RFC8281].  An implementation that supports the Vendor
   Information object, but receives one carrying an Enterprise Number
   that it does not support, MUST ignore the object in the same way as
   described in [RFC7470].

3.  Procedures for the Vendor Information TLV

   The Vendor Information TLV can be used to carry vendor-specific
   information that applies to a specific PCEP object by including the
   TLV in the object.  This includes objects used in Stateful PCE
   extensions such as SRP and LSP objects.  All the procedures as per
   section 3 of [RFC7470].

4.  Vendor Information Object and TLV

   [RFC7470] specify the format of VENDOR-INFORMATION Object and VENDOR-
   INFORMATION-TLV.

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5.  Manageability Considerations

   All manageability requirements and considerations listed in
   [RFC5440], [RFC7470], [RFC8231], and [RFC8281] apply to PCEP protocol
   extensions defined in this document.  In addition, requirements and
   considerations listed in this section apply.

5.1.  Control of Function and Policy

   The requirements for control of function and policy for vendor-
   specific information as set out in [RFC7470] continues to apply to
   Stateful PCEP extensions specified in this document.

5.2.  Information and Data Models

   The PCEP YANG module is specified in [I-D.ietf-pce-pcep-yang].  Any
   standard YANG module will not include details of vendor-specific
   information.  The standard YANG module MAY be extended to include the
   use of this information and the Enterprise Numbers that the object
   and the TLVs contain.

5.3.  Liveness Detection and Monitoring

   Mechanisms defined in this document do not imply any new liveness
   detection and monitoring requirements in addition to those already
   listed in [RFC5440].

5.4.  Verify Correct Operations

   Mechanisms defined in this document do not imply any new operation
   verification requirements in addition to those already listed in
   [RFC5440] and [RFC8231].

5.5.  Requirements On Other Protocols

   Mechanisms defined in this document do not imply any new requirements
   on other protocols.

5.6.  Impact On Network Operations

   Mechanisms defined in [RFC5440] and [RFC8231] also apply to PCEP
   extensions defined in this document.  Further, the mechanism
   described in this document can help the operator to request control
   of the LSPs at a particular PCE.

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6.  IANA Considerations

   There are no IANA consideration in this document.

7.  Implementation Status

   [NOTE TO RFC EDITOR : This whole section and the reference to RFC
   7942 is to be removed before publication as an RFC]

   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".

7.1.  Cisco Systems

   *  Organization: Cisco Systems, Inc.

   *  Implementation: Cisco IOS-XR PCE and PCC

   *  Description: Vendor Information Object used in PCRpt, PCUpd and
      PCInitiate messages.

   *  Maturity Level: Production

   *  Coverage: Full

   *  Contact: ssidor@cisco.com

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8.  Security Considerations

   The protocol extensions defined in this document do not change the
   nature of PCEP.  Therefore, the security considerations set out in
   [RFC5440], [RFC7470], [RFC8231] and [RFC8281] apply unchanged.

   As stated in [RFC6952], PCEP implementations SHOULD support the TCP-
   AO [RFC5925] and not use TCP MD5 because of TCP MD5's known
   vulnerabilities and weakness.  PCEP also support Transport Layer
   Security (TLS) [RFC8253] as per the recommendations and best current
   practices in [RFC9325].

9.  Acknowledgments

   Thanks to Avantika, Mahendra Singh Negi, Udayasree Palle, and Swapna
   K for their suggestions.

10.  References

10.1.  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>.

   [RFC7470]  Zhang, F. and A. Farrel, "Conveying Vendor-Specific
              Constraints in the Path Computation Element Communication
              Protocol", RFC 7470, DOI 10.17487/RFC7470, March 2015,
              <https://www.rfc-editor.org/info/rfc7470>.

   [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>.

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   [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>.

10.2.  Informative References

   [I-D.ietf-pce-pcep-yang]
              Dhody, D., Beeram, V. P., Hardwick, J., and J. Tantsura,
              "A YANG Data Model for Path Computation Element
              Communications Protocol (PCEP)", Work in Progress,
              Internet-Draft, draft-ietf-pce-pcep-yang-22, 11 September
              2023, <https://datatracker.ietf.org/doc/html/draft-ietf-
              pce-pcep-yang-22>.

   [RFC5925]  Touch, J., Mankin, A., and R. Bonica, "The TCP
              Authentication Option", RFC 5925, DOI 10.17487/RFC5925,
              June 2010, <https://www.rfc-editor.org/info/rfc5925>.

   [RFC6952]  Jethanandani, M., Patel, K., and L. Zheng, "Analysis of
              BGP, LDP, PCEP, and MSDP Issues According to the Keying
              and Authentication for Routing Protocols (KARP) Design
              Guide", RFC 6952, DOI 10.17487/RFC6952, May 2013,
              <https://www.rfc-editor.org/info/rfc6952>.

   [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>.

   [RFC8051]  Zhang, X., Ed. and I. Minei, Ed., "Applicability of a
              Stateful Path Computation Element (PCE)", RFC 8051,
              DOI 10.17487/RFC8051, January 2017,
              <https://www.rfc-editor.org/info/rfc8051>.

   [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>.

   [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>.

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Appendix A.  Contributor Addresses

   Dhruv Dhody
   Huawei
   India

   EMail: dhruv.ietf@gmail.com

   Mike Koldychev
   Cisco Systems
   Kanata, Ontario
   Canada

   EMail: mkoldych@cisco.com

Authors' Addresses

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

   Haomian Zheng
   Huawei Technologies
   H1, Huawei Xiliu Beipo Village, Songshan Lake
   Dongguan
   Guangdong, 523808
   China
   Email: zhenghaomian@huawei.com

   Siva Sivabalan
   Ciena
   385 Terry Fox Drive
   Kanata Ontario K2K 0L1
   Canada
   Email: msiva282@gmail.com

   Samuel Sidor
   Cisco Systems, Inc.
   Email: ssidor@cisco.com

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

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