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Updates to SID Verification for SR-MPLS in RFC 8664
draft-chen-pce-sr-mpls-sid-verification-03

Document Type Active Internet-Draft (individual)
Authors Ran Chen , Samuel Sidor , Chun Zhu , Alexej Tokar , Mike Koldychev
Last updated 2022-01-04
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draft-chen-pce-sr-mpls-sid-verification-03
IDR                                                              R. Chen
Internet-Draft                                           ZTE Corporation
Intended status: Standards Track                                S. Sidor
Expires: 8 July 2022                                 Cisco Systems, Inc.
                                                                  C. Zhu
                                                         ZTE Corporation
                                                                A. Tokar
                                                            M. Koldychev
                                                     Cisco Systems, Inc.
                                                          4 January 2022

          Updates to SID Verification for SR-MPLS in RFC 8664
               draft-chen-pce-sr-mpls-sid-verification-03

Abstract

   This document updates [RFC8664] to clarify usage of "SID
   verification" bit signalled in Path Computation Element Protocol
   (PCEP), and this document proposes to define a new flag for
   indicating the headend is explicitly requested to verify SID(s) by
   the PCE.

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
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   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 8 July 2022.

Copyright Notice

   Copyright (c) 2022 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.

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   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 . . . . . . . . . . . . . . . . . . . .   2
   3.  SID verification flag(V-Flag) . . . . . . . . . . . . . . . .   3
     3.1.  Extended V-Flag in SR-ERO Subobject . . . . . . . . . . .   3
     3.2.  Extended V-Flag in SR-RRO Subobject . . . . . . . . . . .   3
   4.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   3
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
     5.1.  SR-ERO Subobject  . . . . . . . . . . . . . . . . . . . .   4
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   7.  Normative References  . . . . . . . . . . . . . . . . . . . .   4
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   4

1.  Introduction

   [I-D.ietf-spring-segment-routing-policy] describes the "SID
   verification" bit usage.  SID verification is performed when the
   headend is explicitly requested to verify SID(s) by the controller
   via the signaling protocol used.  Implementations MAY provide a local
   configuration option to enable verification on a global or per policy
   or per candidate path basis.

   [RFC8664] specifies extensions to the Path Computation Element
   Communication Protocol (PCEP) that allow a stateful PCE to compute
   and initiate Traffic-Engineering (TE) paths, as well as a Path
   Computation Client (PCC) to request a path subject to certain
   constraints and optimization criteria in SR networks.

   This document updates [RFC8664] to clarify usage of "SID
   verification" bit signalled in Path Computation Element Protocol
   (PCEP), and this document proposes to define a new flag for
   indicating the headend is explicitly requested to verify SID(s) by
   the PCE.

2.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

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   cloud transport network: It is usually a national or province
   backbone network to achieve interconnection between multiple regional
   clouds/core clouds deployed in the country/province.

3.  SID verification flag(V-Flag)

3.1.  Extended V-Flag in SR-ERO Subobject

   Section 4.3.1 in Path Computation Element Communication Protocol
   (PCEP) Extensions for Segment Routing [RFC8664] describes a new ERO
   subobject referred to as the "SR-ERO subobject" to carry a SID and/or
   NAI information.  A new flag is proposed in this doucument in the SR-
   ERO Subobject for indicating the pcc is explicitly requested to
   verify SID(s) by the PCE.

   The format of the SR-ERO subobject as defined in [RFC8664] is:

        0                   1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |L|   Type=TBD  |     Length    |  NT   |     Flags   |V|F|S|C|M|
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                         SID (optional)                        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       //                   NAI (variable, optional)                  //
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                 Figure 1

   V: When the V-Flag is set then PCC MUST consider the "SID
   verification" as described in Section 5.1 in
   [I-D.ietf-spring-segment-routing-policy].

   The other fields in the SR-ERO subobject is the same as that of the
   SR-ERO subobject as defined in [RFC8664].

3.2.  Extended V-Flag in SR-RRO Subobject

   The format of the SR-RRO subobject is the same as that of the SR-ERO
   subobject, but without the L-Flag, per [RFC8664].

   The V flag has no meaning in the SR-RRO and is ignored on receipt at
   the PCE.

4.  Acknowledgements

   TBD.

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5.  IANA Considerations

5.1.  SR-ERO Subobject

   This document defines a new bit value in the sub-registry "SR-ERO
   Flag Field" in the "Path Computation Element Protocol (PCEP) Numbers"
   registry.

                Bit     Name                         Reference
                TBA    SID verification(V)           This document

                                  Figure 2

6.  Security Considerations

   TBD.

7.  Normative References

   [I-D.ietf-spring-segment-routing-policy]
              Filsfils, C., Talaulikar, K., Voyer, D., Bogdanov, A., and
              P. Mattes, "Segment Routing Policy Architecture", Work in
              Progress, Internet-Draft, draft-ietf-spring-segment-
              routing-policy-14, 25 October 2021,
              <https://datatracker.ietf.org/doc/html/draft-ietf-spring-
              segment-routing-policy-14>.

   [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>.

   [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>.

Authors' Addresses

   Ran Chen
   ZTE Corporation
   Nanjing
   China

   Email: chen.ran@zte.com.cn

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   Samuel Sidor
   Cisco Systems, Inc.

   Email: ssidor@cisco.com

   Chun Zhu
   ZTE Corporation
   Nanjing
   China

   Email: zhu.chun1@zte.com.cn

   Alex Tokar
   Cisco Systems, Inc.

   Email: atokar@cisco.com

   Mike Koldychev
   Cisco Systems, Inc.

   Email: mkoldych@cisco.com

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