Hi Saumya,

Pitching in here as I do the AD evaluation for the link-bandwidth draft. In
my opinion, neither of these are directly related to the link bandwidth
draft.

The first point seems to be about general BGP UPDATE message packing that
is applicable to any attribute and not specific to the LBW ExtCom. I can't
remember off the top of my head if the topic of BGP update packing is
covered by any RFC/draft but you can fork a new thread on IDR for
discussion around it.

The second point is use of the LBW ExtCom for EVPN and as such it is better
covered in a BESS document. I am not sure if draft-ietf-bess-ebgp-dmz is
that document or if there is another more appropriate one. I'll request you
to start a separate thread on it and the BESS chairs to guide.

I hope this helps.

Thanks,
Ketan


On Wed, Aug 20, 2025 at 4:42 PM Dikshit, Saumya <saumya.dikshit=
[email protected]> wrote:

> Please help me with the below email.
>
> Thanks,
>
> Saumya.
> *From: *Dikshit, Saumya <[email protected]>
> *Date: *Monday, 18 August 2025 at 5:00 PM
> *To: *Jeffrey Haas <[email protected]>
> *Cc: *BESS <[email protected]>, [email protected] <[email protected]>
> *Subject: *[bess] Re: WGLC for draft-ietf-idr-link-bandwidth (Ending 1
> August, 2025)
>
> Hi Jeff,
>
> Please see inline with tag [saumya]
>
>
>
> On Wed, Aug 06, 2025 at 07:07:59PM +0000, Dikshit, Saumya wrote:
> > I support the progression of this draft. Though I have few
> queries/clarifications:
> >
> > Is the definition of a link restricted to the underlay physical links or
> also mapped to logical ones like  TE-links mapping to a tunnel.
> > For example, a bandwidth tied to a VPN tunnel stitching two fabrics over
> WAN. (like a multisite deployment).
> >
> > Can we clarify the definition of the “link” if it’s not implicit.
>
> >From the first part of the draft:
> >: The Link Bandwidth Extended Community is defined as a BGP extended
> community
> >: that carries the bandwidth information of a router, represented by BGP
> >: Protocol Next Hop, connecting to remote network.
>
> >So, while the definition of a "link" is left vague in the specification,
> >it's clear in context that it's tied to a BGP next hop.
>
> [saumya] How I am seeing this is
>
>    - only one instance of* “*bandwidth extended community “ can be
>    carried in one BGP update message.
>       - And BGP update message encapsulation procedures are expected to
>       bucket as many NRLI’s as possible that share the next hop
>    - The choice of NLRI’s to be coupled with this extended community
>       - may not be just plain vanilla pointing to same next-hop
>       - but also might be driven via other policies as well.
>    - This will require a mention of these procedures with MAY clause,
>    since this draft is about this new extended community.
>
>
> >In terms of deployment use cases, it's not limited in this specification.
> >One of the discussions overlapping the feature is that the same community
> >can be used in-context for multiple things from underlay, to overlay, to
> >load balancing traffic across a provider core for Internet purposes.  The
> >draft, covering primarily encoding, doesn't try to restrict the use cases.
>
> [saumya] The usage specifically with Overlay Index.
>
>    - Should this newly attribute be carried with the UPDATE message
>    publishing the prefix as NLRI
>    - Or with the update message carrying the next-hop-resolution.
>    - For example, for EVPN RT-5’s carrying overlay index pointing to
>    RT-2’s and RT-1’s.
>       - Will this attribute be carried with with RT-5 or RT-2/1 which
>       resolve the route and carries the flattened next-hop
>
>
>
> >Some of the BESS discussion covering LBW covers these points along with
> the
> >operational use case for things like accumulation at multipath merge
> points.
> >I'd suggest familiarizing yourself with those drafts.
>
> [saumya] I couldn’t get any reference to its usage with Overlay index in
> bess or idr.  It will be great to have pointer to the drafts. Else we need
> to call out above bullets somewhere.
>
> I think overlay index usage is very important.
>
>
>
> >IDR will be coordinating with BESS to figure out the long term disposition
> >of those drafts now that the protocol component draft is moving forwarding
> >towards publication.
>
> Thanks,
>
> Saumya.
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