Subject: [straw] Next steps on the RTCP draft

From: Lorenzo Miniero <[email-masked]>
Date: Wed, 23 Apr 2014 14:46:37 +0200

Hi all,

a bit later than I wanted, I was starting to re-order the feedback
I got in London on the RTCP draft during the STRAW session. After
reviewing the recording, the notes, mniutes, etc., I realized that,
while there are some points that have been definitely clarified, some
couldn't be fully addressed, due to lack of f2f time.

There definitely was agreement, for instance, on the need to rewrite
the CSRC list, to take into account more RTCP messages besides the AVPF
feedback that is currently addressed, that you can't really write a
generic guideline for future RTCP messages that may be defined later on,
that there are other aspects to take into account (e.g., the a=rtcp SDP
attribute that can mess up, payload types that may change, etc.) and so
on.

A point that had a long discussion but was left unclear, though, is the
one related to the taxonomies/topologies as they are addressed in the
current version of the doc. While the terminology definitely needs to be
improved in general (again, my fault) to avoid ambiguities, there
apparently was not consensus on what exactly should be used as a basis
for the document: namely, whether keeping the RFC7092 STRAW taxonomy
the document tries to refer to as of now (updating it as needed, since
it currently refers to the pre-RFC one that had some changes in the
meanwhile), or changing the organization of the draft to have it refer
to the RTP Topologies update draft.

I had some slides on that, since it was one of the points discussed by
Albrecht Schwarz on the AVTCORE list, but unfortunately we had to close
the discussion a couple of slides before. Nevertheless, we had already
had the chance to start discussing the matter before that. You can find
the slides here, for some more details on that:

    http://www.ietf.org/proceedings/89/slides/slides-89-straw-0.pdf

The discussion basically was about whether we really needed to involve
RTP topologies in the document, or whether the STRAW taxonomy was
indeed more suited to describing the different approaches an interested
component (according to where in taxonomy it would fall) could take.

Needless to say, taking a decision on this specific point would be
quite important, as a change in perspective there would require a
refactoring of the whole document to more aptly address the scenarios
to take into account, and so I'd like to be sure I'm on the right path
before starting to work on a new version of the draft.

What are your thoughts about that?

Thanks,
Lorenzo

---

From: Paul Kyzivat <[email-masked]>
Date: Wed, 23 Apr 2014 10:57:51 -0400

Lorenzo,

On 4/23/14 8:46 AM, Lorenzo Miniero wrote:

[snip]

> to the RTP Topologies update draft.

[snip]

> component (according to where in taxonomy it would fall) could take.

My understanding of the discussion was that it is a problem if the straw 
taxonomy is incompatible with the RTP topologies. that are missing from 
the RTP topologies.

ISTM it would be worthwhile to expend some effort comparing those two 
documents and trying to correlate them. If we were lucky, there might be 
a straightforward correlation. (Though it might not be 1:1.) Or it might 
turn out that straw has identified topologies that are missing from the 
RTP topologies draft and ought to be added there.

I don't think it should be a job of your draft to do that. It might be a 
new milestone for straw. Whether that means progression of your draft 
should be delayed is something that should be part of the discussion.

	Thanks,
	Paul

---

From: "Gonzalo Salgueiro (gsalguei)" <[email-masked]>
Date: Wed, 23 Apr 2014 15:35:26 +0000

On Apr 23, 2014, at 10:57 AM, Paul Kyzivat <[email-masked]> wrote:

> My understanding of the discussion was that it is a problem if the straw taxonomy is incompatible with the RTP topologies. that are missing from the RTP topologies.
> 
> ISTM it would be worthwhile to expend some effort comparing those two documents and trying to correlate them. If we were lucky, there might be a straightforward correlation. (Though it might not be 1:1.) Or it might turn out that straw has identified topologies that are missing from the RTP topologies draft and ought to be added there.

As a side note: I think it was also mentioned that this document, among several others, should adhere to the rtp taxonomy draft (draft-ietf-avtext-rtp-grouping-taxonomy).  I do think this is something that can/should be enforced.

Cheers,

Gonzalo

> 
> I don't think it should be a job of your draft to do that. It might be a new milestone for straw. Whether that means progression of your draft should be delayed is something that should be part of the discussion.
> 
> 	Thanks,
> 	Paul
> 
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