[Cerowrt-devel] [Cake] mo bettah open source multi-party videoconferncing in an age of bloated uplinks?

David Lang david at lang.hm
Fri Mar 27 15:12:27 EDT 2020

On Fri, 27 Mar 2020, David P. Reed wrote:

> Congestion control for real-time video is quite different than for streaming. Streaming really is dealt with by a big enough (multi-second) buffering, and can in principle work great over TCP (if debloated).
> UDP congestion control MUST be end-to-end and done in the application layer, which is usually outside the OS kernel. This makes it tricky, because you end up with latency variation due to eh OS's process scheduler that is on the order of magnitude of the real-time requirements for air-to-air or light-to-light response (meaning the physical transition from sound or picture to and from the transducer).

at some level this is correct, but if the link is clogged with TCP packets, it 
doesn't matter what your UDP application attempts to do, so installing cake to 
keep individual links from being too congested will allow your UDP application 
have a chance to operate.

David Lang

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