Updates to SID Verification for SR-MPLS in RFC 8664

Introduction 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. 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 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.

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. 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.

SID verification flag(V-Flag)

Extended V-Flag in SR-ERO Subobject Section 4.3.1 in Path Computation Element Communication Protocol (PCEP) Extensions for Segment Routing 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 is:

V: When the V-Flag is set then PCC MUST consider the "SID verification" as described in Section 5.1 in . The other fields in the SR-ERO subobject is the same as that of the SR-ERO subobject as defined in .

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

Acknowledgements TBD.

IANA Considerations

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.

Security Considerations TBD.