[Idr] Re: Last Call: <draft-ietf-idr-sr-policy-safi-09.txt> (Advertising Segment Routing Policies in BGP) to Proposed Standard

[Ketan Talaulikar <[e-mail]>]

Hi Rajesh,

Thanks for your review and comments.

It is necessary to encode the SRv6 SID value first for encoding the
optional SRv6 Endpoint Behavior and Structure. This is something that
was not clear in the text in the two drafts and was brought up by Russ
in his GenART review - please refer to [1]. Your query is related to
the same and we'll clarify the text about the use of value 0 in such
scenarios.

I'll share the proposed text later today.

Thanks,
Ketan

[1] https://mailarchive.ietf.org/arch/msg/idr/eEh7C902VY4FqujW7ul7mRnumt4/

On Sat, Nov 2, 2024 at 12:36 AM Rajesh MV <[e-mail]> wrote:
>
> Hello authors,
>
>
> The encoding for the SRv6 BSID TLV requires the BSID to be present for signaling the Endpoint and Structure information. When a controller prefers not to specify the BSID (i.e., dynamic BSID allocation in the router) but still wants to indicate the desired behavior and structure, it can set the SRv6 BSID field to 0 with the S flag set to 0 and the B flag set to 1. Similarly, if the controller wants to specify flags (Eg: I-Flag) without providing a BSID, it can set the SRv6 BSID field to 0 and the S flag  to 0. Is this correct ? The draft does not seem to clarify this. This is also the case for the segment types in draft-ietf-idr-bgp-sr-segtypes-ext where the SRv6 SID is optional.
>
>
> Regards
>
> Rajesh
>
>
> ========================================================================================================
>
> The IESG has received a request from the Inter-Domain Routing WG (idr) to
> consider the following document: - 'Advertising Segment Routing Policies in
> BGP'
>   <draft-ietf-idr-sr-policy-safi-09.txt> as Proposed Standard
>
> The IESG plans to make a decision in the next few weeks, and solicits final
> comments on this action. Please send substantive comments to the
> [e-mail] mailing lists by 2024-11-11. Exceptionally, comments may
> be sent to [e-mail] instead. In either case, please retain the beginning
> of the Subject line to allow automated sorting.
>
> Abstract
>
>
>    A Segment Routing (SR) Policy is an ordered list of segments (i.e.,
>    instructions) that represent a source-routed policy.  An SR Policy
>    consists of one or more candidate paths, each consisting of one or
>    more segment lists.  A headend may be provisioned with candidate
>    paths for an SR Policy via several different mechanisms, e.g., CLI,
>    NETCONF, PCEP, or BGP.
>
>    This document specifies how BGP may be used to distribute SR Policy
>    candidate paths.  It introduces a BGP SAFI to advertise a candidate
>    path of a Segment Routing (SR) Policy and defines sub-TLVs for the
>    Tunnel Encapsulation Attribute for signaling information about these
>    candidate paths.
>
>    This documents updates RFC9012 with extensions to the Color Extended
>    Community to support additional steering modes over SR Policy.
>
>
>
>
> The file can be obtained via
> https://datatracker.ietf.org/doc/draft-ietf-idr-sr-policy-safi/
>
>
> The following IPR Declarations may be related to this I-D:
>
>    https://datatracker.ietf.org/ipr/2984/
>    https://datatracker.ietf.org/ipr/5890/
>    https://datatracker.ietf.org/ipr/5891/
>
>
>
> The document contains these normative downward references.
> See RFC 3967 for additional information:
>     rfc4272: BGP Security Vulnerabilities Analysis (Informational - Internet Engineering Task Force (IETF) stream)
>     draft-ietf-idr-bgp-ls-sr-policy: Advertisement of Segment Routing Policies using BGP Link-State (None - Internet Engineering Task Force (IETF) stream)
>     draft-ietf-idr-bgp-sr-segtypes-ext: Segment Routing Segment Types Extensions for BGP SR Policy (None - Internet Engineering Task Force (IETF) stream)
>     rfc6952: Analysis of BGP, LDP, PCEP, and MSDP Issues According to the Keying and Authentication for Routing Protocols (KARP) Design Guide (Informational - Internet Engineering Task Force (IETF) stream)
>
>