Re: [AVTCORE] draft-ietf-avtcore-multi-party-rtt-mix-08.txt - please review

Paul Kyzivat <> Mon, 12 October 2020 15:04 UTC

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From: Paul Kyzivat <>
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Subject: Re: [AVTCORE] draft-ietf-avtcore-multi-party-rtt-mix-08.txt - please review
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On 10/12/20 10:35 AM, Gunnar Hellström wrote:
> Paul, thanks for the review,
> I have accepted all your proposals and done the easy ones in my draft.
> Will continue with the proposed restructuring of section 2.1.

Sounds good.

> See a few comments below.

I have one followup comment below.

> Den 2020-10-10 kl. 20:50, skrev Paul Kyzivat:

>> * Section 2.1:
>> Why was "rtt-mix-rtp-mixer" chosen as the name of the attribute? It 
>> seems cumbersome and redundant. Wouldn't "rtt-mixer" be sufficient?
> Yes, a better name may be needed.
> draft-hellstrom-avtcore-multi-party-rtt-solutions has in sections 6.3 
> and 6.4 a discussion on the sdp attribute. I agree that the name is long 
> and maybe confusing. The thought is that the first part, "rtt-mix", 
> indicates the purpose: to indicate support for a type of mixer for 
> real-time text. The second part, "rtp-mixer", indicates what type of 
> mixer that is supported. It is the rtp-mixer style as described in RFC 
> 3550.
> There is no plan right now, but it would be possible that later work 
> specifies another mixer type as an alternative. It could be a 
> multi-stream mixer using the rtp-translator style from RFC 3550. That 
> work could then register another attribute, e.g. called 
> "rtt-mix-rtp-translator". That is not sufficiently likely to motivate 
> the effort to now create an attribute with values, but the reasoning 
> motivated a name that indicates both the purpose and the solution.
> That said, looking at your name proposal "rtt-mixer", I find that it can 
> meet the criteria. "rtt-" indicates that it is about real-time text, and 
> "mixer" can be taken to mean the "rtp-mixer" style. It was also used as 
> the name in early versions of this draft.
> So, the simple conclusion is: Yes, accepted and done.

When I looked at "rtt-mix-rtp-mixer" my first thought was as you 
describe - that there would be several attributes pertaining to rtt 
mixers. But then I found no others in the draft, and none starting with 
"rtt-mix" already in the iana registry. So simplifying seemed in order.

But, if you foresee some possibility of others being defined in the 
future then it might indeed be worth planning for that now. As you see 
fit, or perhaps it should be further discussed.