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Networking Working Group                                       Ran. Chen
Internet-Draft                                                 Zhu. Chun
Intended status: Standards Track                         ZTE Corporation
Expires: August 6, 2021                                 February 2, 2021


            PCEP Extensions for sid verification for SR-MPLS
               draft-chen-pce-sr-mpls-sid-verification-00

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
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   This Internet-Draft will expire on August 6, 2021.

Copyright Notice

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   described in the Simplified BSD License.



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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions used in this document . . . . . . . . . . . . . .   2
   3.  SID verification flag(V-Flag) . . . . . . . . . . . . . . . .   2
     3.1.  Extended V-Flag in SR-ERO Subobject . . . . . . . . . . .   2
     3.2.  Extended V-Flag in SR-RRO Subobject . . . . . . . . . . .   3
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   3
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   3
     5.1.  SR-ERO Subobject  . . . . . . . . . . . . . . . . . . . .   3
   6.  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.  Conventions used in this document

   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 RFC2119.

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-



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   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=36   |     Length    |  NT   |     Flags   |V|F|S|C|M|
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                         SID (optional)                        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       //                   NAI (variable, optional)                  //
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

            Figure 1 SR-ERO Subobject Format of extended V-Flag

   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] .

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.  Security Considerations

   TBD.

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
                  7    SID verification(V)           This document





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6.  Normative references

   [I-D.ietf-spring-segment-routing-policy]
              Filsfils, C., Talaulikar, K., Voyer, D., Bogdanov, A., and
              P. Mattes, "Segment Routing Policy Architecture", draft-
              ietf-spring-segment-routing-policy-09 (work in progress),
              November 2020.

   [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

   Email: chen.ran@zte.com.cn


   Chun Zhu
   ZTE Corporation

   Email: zhu.chun1@zte.com.cn

























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