Re: [rtcweb] Changing video size (Re: use case:)

[Harald Alvestrand <[e-mail]>]

On 06/21/11 09:45, Varun Singh wrote:
> In case of RTP, RTCP carries network level reception statistics and video/voice metrics (RTCP XR etc). However, there is a no standardized congestion control for RTP (http://tools.ietf.org/html/draft-gharai-avtcore-rtp-tfrc-00 uses packet loss and delay not some of the other cues mentioned in the mail).
>
> Unless we identify a congestion control, I would suggest that the use-case capture that we need an extensible mechanism to carry this type of information and then the sender implements its own congestion control (best to its ability).
>
I think we need to separate the two requirements:

- response to network conditions (congestion control)
- response to recipient system conditions such as window size, CPU load, 
window being obscured, and so on.

Even though the possible actions to take might be the same, the two are 
fundamentally different; responses to end system events concern only the 
sender and the recipient, while responses to congestion events have the 
requirement that the behavior be globally sensible - that is, works well 
with the algorithms deployed by other users of the network.

                          Harald