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
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on 8 July 2022.
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Please review these documents carefully, as they describe your rights
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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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