Re: [IPv6] WG Adoption call for Segment Routing Header encapsulation for Alternate Marking Method

Hi Joel/All,

I share some of the questions and concerns of the chairs and other WG
members.

Perhaps we need to give more time to the authors to add clarifying text to
the draft (what has been said on the list).

I suggest a dedicated section towards the start of the document that *only*
focuses on why this mechanism is needed in addition to RFC9343. It would be
interesting if there is any analysis from the implementation/deployment of
RFC9343 that has shown it to be not suitable for SRv6 deployments.

Thanks,
Ketan

On Thu, Feb 2, 2023 at 6:14 AM Joel Halpern <jmh@joelhalpern.com> wrote:

> This call is for the draft at:
> https://datatracker.ietf.org/doc/draft-fz-spring-srv6-alt-mark
>
> This email starts the WG adoption call for the subject draft (as
> requested by the authors, with apologies from the WG chairs for how long
> it has taken to kick this out.)  This call will run through the end of
> the day on Feb 16.  Pleaes read the whole email as there are a few
> points, and it is not that long.
>
> Please comment on whether you think this topic is something you think
> the spring WG should work, whether you think this draft is a good
> starting point for such work, any issues or concerns you have, and
> whether you would be willing to help be contributing and / or reviewing
> the work if the WG does choose to work on it.
>
> 6man is copied for their information, as this is different from but
> related to an extension header proposal in front of 6man.
>
> Authors and named contributors, please confirm to the list that all
> known, relevant, IPR has been disclosed.  If it has note, please remedy
> this gap.
>
> The spring chairs have noted one aspect of this draft that caught our
> eye, and we would appreciate WG members who comment on the adoption to
> consider, and if possible opine, on this.  As we read this draft, as
> distinct from the related 6man extension header work, this causes the
> recorded altmarks to only be updated at routers identified in the SRH
> segment list.  (We presume this would include all identified points in a
> compressed container.) We could not tell from the document what the
> value was for this as distinct from getting the measurements at all
> routers.  Do WG members understand and agree that it does have value?
>
> As a lesser point, we consider that one quote in the draft is misleading
> and will likely need to be reworded in the near future.  The draft say
> "SRH TLV can also be used to encode the AltMark Data Fields for SRv6 and
> to monitor every node along the SR path."  It is unclear if these was
> intended to mean all routers (most of which would not see this TLV) or
> if it was intended to refer to only those routers identified in the SRH,
> in which case we presume it will be reworded.
>
> Thank you,
>
> Joel
>
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