Re: [tsvwg] (transport) RE: Advance notice on request to poll TSVWG for adoption of draft-kaippallimalil-tsvwg-media-hdr-wireless-03

["C. M. Heard" <[e-mail]>]

On Tue, Oct 31, 2023 at 7:20 AM Kaippallimalil John <
[e-mail]> wrote:

> Hi,
>
> Thanks for this feedback. Much of it has been factored into the proposed
> revision to use MED in outer packet UDP option for now.
>
> Further responses tagged with [JK]:
>
> > But the big elephant in the room is that draft-ietf-tsvwg-udp-options
> > exclusively defines TRANSPORT options designed to be consumed by
> > endpoints, not NETWORK options designed to be inspected by routers or
> > other middleboxes. If draft-kaippallimalil-tsvwg-media-hdr-wireless-03
> > is to be adopted as a basis for future work, then in my opinion one of
> the
> > adoption questions should be whether the WG would be willing to make this
> > change of direction to draft-ietf-tsvwg-udp-options.
> >
> > The rather lengthy previous discussion pretty much left this last point
> up in
> > the air, but I came away with the conclusion that trying to fix
> > IPv6 HbH options is probably the better alternative in the long run.
>
>         [JK] The authors discussed this and related notes from Alex with
> the various trade-offs of each of the transports.
> For this draft, MED in outer UDP packet option from server (Provider-A) to
> wireless node (Provider-B) is sufficient.
> The only potential drawback may be that the option at the end of the
> packet may affect performance, or may not depending on the implementation.
>

If there is no inspection by middleboxes, just generation/consumption by
tunnel endpoints, then the usage of UDP Options would be as intended in the
current specification, and the elephant will have quietly exited the room.

The possibility still exists to use per-fragment options to address the
performance issues, as those are currently in the UDP Options spec. If that
is seen as desirable or useful, and if it would predominantly be used with
atomic fragments, it may be possible to add a 3rd FRAG option format for
this purpose (it would have utility in more general situations).

Mike Heard