Re: [Dart] draft-dart-dscp-rtp - way forward

Ben Campbell <ben@nostrum.com> Thu, 28 August 2014 19:34 UTC

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From: Ben Campbell <ben@nostrum.com>
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Date: Thu, 28 Aug 2014 14:33:45 -0500
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To: Colin Perkins <csp@csperkins.org>
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Cc: "Black, David" <david.black@emc.com>, "dart@ietf.org" <dart@ietf.org>
Subject: Re: [Dart] draft-dart-dscp-rtp - way forward
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On Aug 28, 2014, at 1:22 PM, Colin Perkins <csp@csperkins.org>; wrote:

>> [B] Open issue: PHBs and DSCPs for RTCP.  The RTCP guideline bullet cannot
>> be revised until this open issue is resolved on the list.  See:
>> 	http://www.ietf.org/mail-archive/web/dart/current/msg00156.html
>> 
>> --> I think I see rough agreement that for RTCP SRs, the same DSCP should
>> --> be used as the RTP stream being reported on, and for RTCP RRs, the 
>> --> DSCP to use should be the one that would be used to send a similar
>> --> RTP stream.
> 
> The distinction between RTCP SR and RR isn’t useful here. What you want to say is that an SSRC needs to use the same marking for the RTCP packets it sends as it uses for the RTP packets it sends. If it doesn’t send any RTP packets, it marks its RTCP packets with the marking it would use if it did send RTP.

That last bit concerns me a bit. Are we really asking an implementation to figure out how it would have done something it isn't going to do?