[Dart] Open Issue: Guidance for RTCP
Ben Campbell <ben@nostrum.com> Mon, 25 August 2014 05:00 UTC
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From: Ben Campbell <ben@nostrum.com>
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Date: Mon, 25 Aug 2014 00:00:15 -0500
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Subject: [Dart] Open Issue: Guidance for RTCP
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(as chair) We have an open issue (Designated issue [B] by David) about what guidance to give about RTCP in draft-ietf-dart-dscp-rtp. We need to close this in order to progress the draft--meaning we need to do so ASAP. Please look at the the following quoted text for background, and offer an opinion: > (2) PHBs and DSCPs for RTCP. > > I'm not sure what to say about this, as it looks like I need to set > off a discussion (debate?) between you and my co-author, Paul Jones. > > Colin (from WGLC comments): > > > Rather, within a single RTP session there are RTCP packets sent > > that give information about the RTP streams that are being sent, and that > > report on the reception quality of RTP streams being received. Using a single > > PHB and DSCP for all RTCP packets within an RTP session might make sense, but > > it's important to note that one role of RTCP is to provide an estimate of the > > round-trip time seen by the media, so the PHB/DSCP will have to be chosen with > > care to avoid biasing that estimate too much. > > Paul (from shortly after the Toronto meeting: > > > During the meeting, there was discussion of marking RTCP packets. Some > > notes I received on this topic suggested that it was proposed that RTCP > > should be marked the same as for RTP. The argument was that this is used > > for RTT calculations. If that is what was said, I'd like to state my > > disagreement. :-) > > > > The forward and reverse paths are not necessarily the same and there is > > nothing one should assume about the reverse path to provide guidance about > > the forward path (or vice versa). As perhaps a gross example, I have the > > ability to download far faster on my home Internet connection than I can > > upload. Other important traffic characteristics differ in each direction. > > > > Further, an RTCP packet might provide information related to several different > > RTP packets. I certainly would not want to see one RTCP packet per RTP packet. > >
- [Dart] Open Issue: Guidance for RTCP Ben Campbell
- Re: [Dart] Open Issue: Guidance for RTCP Black, David
- Re: [Dart] Open Issue: Guidance for RTCP Harald Alvestrand