Hi PK, Thanks for your review and including the BGP draft authors to keep them posted.
Please check inline below. From: spring <spring-boun...@ietf.org> On Behalf Of Przemyslaw Krol Sent: 24 October 2018 23:35 To: spring@ietf.org Subject: [spring] draft-previdi-idr-segment-routing-te-policy - BSID flag inconsistency Authors, There seems to be a discrepancy in BSID flag ordering: https://tools.ietf.org/html/draft-ietf-idr-segment-routing-te-policy-04#section-2.4.2 0 1 2 3 4 5 6 7 +-+-+-+-+-+-+-+-+ |S|I| | +-+-+-+-+-+-+-+-+ https://tools.ietf.org/html/draft-ietf-idr-segment-routing-te-policy-04#section-8.5 Bit Description Reference --------------------------------------------------------------------------------- 0 Drop Upon Invalid Flag (I-Flag) This document 1 Specified-BSID-Only Flag (S-Flag) This document Would it be possible to clarify this please? [KT] Thanks for catching that it looks like perhaps the IANA section needs to be updated to reflect the ordering in the main section text. Also, draft mentions "V-flag: Segment Verification Flag": V-Flag: This flag encodes the "Segment Verification" behavior. It is used by SRPM as described in section 5 in [I-D.ietf-spring-segment-routing-policy]. Yet its meaning doesn't look to be clearly described in either drafts. [KT] I believe this is referring to the following text in Sec 5.1 of the draft-ietf-spring-segment-routing-policy. o It is empty. o Its weight is 0. o The headend is unable to perform path resolution for the first SID into one or more outgoing interface(s) and next-hop(s). o The headend is unable to perform SID resolution for any non-first SID of type 3-through-11 into an MPLS label or an SRv6 SID. o The headend verification fails for any SID for which verification has been explicitly requested. "Unable to perform path resolution" means that the headend has no path to the SID in its SR database. SID verification is performed when the headend is explicitly requested to verify SID(s) by the controller via the signaling protocol used. Normally, only the path resolution is needed to be performed and that too for the first SID. The “V” flag may be used to indicate to the headend to perform the verification. When the SID is of type 1 or 2 then it is only about checking the path resolution (reachability) for it. When the SID is of type 3-through-11 then it would be about first resolving to get the SID value and then doing its path resolution. Perhaps this text in the SR Policy Architecture draft could clarify this further (if needed) and we use “SID verification” term in the BGP draft for alignment of terminologies. Thanks, Ketan thanks, pk -- Przemyslaw "PK" Krol | Strategic Network Engineer ing | pk...@google.com<mailto:pk...@google.com>
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