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