Re: [rtcweb] Draft proposal for updating Multiparty topologies in draft-ietf-rtcweb-rtp-usage

Magnus Westerlund <magnus.westerlund@ericsson.com> Fri, 02 May 2014 08:39 UTC

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Date: Fri, 2 May 2014 10:39:42 +0200
From: Magnus Westerlund <magnus.westerlund@ericsson.com>
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To: "Cullen Jennings (fluffy)" <fluffy@cisco.com>
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Subject: Re: [rtcweb] Draft proposal for updating Multiparty topologies in draft-ietf-rtcweb-rtp-usage
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On 2014-04-30 23:56, Cullen Jennings (fluffy) wrote:
> 
> On Apr 15, 2014, at 9:14 AM, Magnus Westerlund
> <magnus.westerlund@ericsson.com> wrote:
> 
>> This limitation means that some of the RTP middlebox-based
>> topologies are not suitable for use in the WebRTC environment.
>> Specifically:
>> 
>> o  Video switching MCUs (Topo-Video-switch-MCU) SHOULD NOT be
>> used, since they make the use of RTCP for congestion control and
>> quality of service reports problematic (see Section 3.8 of 
>> [I-D.ietf-avtcore-rtp-topologies-update]).
> 
> I think this is deserving of some WG discussion as people may not be
> up to speed of what this is allowing or not allowing. My
> understanding was several companies at the last WebRTC Expo
> conference were demonstrating system that used this type of MCU.
> 
> If SRTP were more flexible and there was a way to a mixer work
> without giving it the keys to the decrypt the media, I think people
> would be keener on mixers but right it seems like the pro / cons
> invovle a trade off between significant security functionally loss
> and possible loss of some RTCP data which many systems totally
> ignore.  Anyway, not taking any opinion other than this seems like a
> significant enough change to have some discussion on it.
> 

WG,

The change is in the document currently in WG last call. So please
review the whole context, and please do read the topologies document so
that you have a real understanding of what a topology means. The
topology names can be misinterpreted if one only looks at the high
level, not the details of the RTP/RTCP behaviour the topology discusses.

Cheers

Magnus Westerlund

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