Internet-Draft SID Verification for SR-MPLS Updates July 2022
Chen, et al. Expires 9 January 2023 [Page]
Workgroup:
IDR
Internet-Draft:
draft-chen-pce-sr-mpls-sid-verification-04
Published:
Intended Status:
Standards Track
Expires:
Authors:
R. Chen
ZTE Corporation
S. Sidor
Cisco Systems, Inc.
C. Zhu
ZTE Corporation
A. Tokar
Cisco Systems, Inc.
M. Koldychev
Cisco Systems, Inc.

Updates to SID Verification for SR-MPLS in RFC 8664

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 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 9 January 2023.

Table of Contents

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].

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.

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-22, , <https://datatracker.ietf.org/doc/html/draft-ietf-spring-segment-routing-policy-22>.
[RFC2119]
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <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, , <https://www.rfc-editor.org/info/rfc8664>.

Authors' Addresses

Ran Chen
ZTE Corporation
Nanjing
China
Samuel Sidor
Cisco Systems, Inc.
Chun Zhu
ZTE Corporation
Nanjing
China
Alex Tokar
Cisco Systems, Inc.
Mike Koldychev
Cisco Systems, Inc.