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

"Black, David" <david.black@emc.com> Thu, 28 August 2014 19:41 UTC

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From: "Black, David" <david.black@emc.com>
To: Ben Campbell <ben@nostrum.com>, Colin Perkins <csp@csperkins.org>
Date: Thu, 28 Aug 2014 15:41:38 -0400
Thread-Topic: [Dart] draft-dart-dscp-rtp - way forward
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Subject: Re: [Dart] draft-dart-dscp-rtp - way forward
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> > 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?

Yes, --David

> -----Original Message-----
> From: Ben Campbell [mailto:ben@nostrum.com]
> Sent: Thursday, August 28, 2014 3:34 PM
> To: Colin Perkins
> Cc: Black, David; dart@ietf.org
> Subject: Re: [Dart] draft-dart-dscp-rtp - way forward
> 
> 
> 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?