[R-C] Request for agenda time in Paris to discuss RTP congestion control proposals

[Harald Alvestrand]

Hello,

our transport AD, Wesley Eddy, suggested I should contact you about the 
issue of getting discussion time at the Paris IETF for the problem of 
congestion control for RTP-carried real-time media.

We (a small group of people working on the rtp-congestion at alvestrand.no 
mailing list) have come up with a few drafts, mainly based on work done 
at Global IP Sound and Google:

- draft-alvestrand-rtcweb-congetsion-01
- draft-alvestrand-rmcat-remb-00

These drafts suggest that one implement a delay-based, 
recipient-measured estimation algorithm for bandwidth estimation over 
RTP flows, and define a feedback message (analogous to TMMBR) for the 
recipient telling the sender how much data to send at any time.

There has also been discussion on the rtcweb mailing list about the 
desirable properties of such congestion control, including how it should 
interact with congestion control in SCTP, which is suggested for a data 
channel transport in the RTCWEB effort.

In an informal lunch meeting in Taipei, we discussed having a 
three-pronged approach:

- Defining a set of best practices for what one should really not do 
with RTP flows (such as saying "when packet loss exceeds some 
percentage, reduce send rate significantly"); this seems like 
appropriate work for AVTCORE

- Define a set of feedback messages that can be used to implement 
algorithms like the one mentioned above, or others, without 
standardizing the algorithm itself

- Creating a working group for publishing the ideas and pushing a long 
term effort for standardizing a congestion control algorithm. A draft 
charter is here: http://www.ietf.org/iesg/evaluation/rmcat-charter.txt

Due to bad planning, we did not get a BOF request in for the Paris 
meeting, but would really like to have a place to have this discussion 
in that timeframe; also, the ICCRG should have quite a few people whose 
input we would definitely want into this discussion.

Can you consider whether or not you can offer us some time on the ICCRG 
agenda for this?

                     Harald Alvestrand