[rtcweb] Proposal: require rtcp-mux (remove non-muxed RTCP; it would be Christmas in July!)

[Peter Thatcher <[e-mail]>]

At IETF 93 last week,  Cullen pointed out that he looked into ICE endpoints
and found that all of them support rtcp-mux.  Inspired by that, I went
around and asked about a dozen people "would you be OK if we removed
support for non-muxed RTCP?"  The range of responses went from "I'm OK with
it if Cullen is" to "yeah, that would be great".  No one said no.  Cullen
said yes.

For me, removing support for non-muxed RTCP would be like Christmas in
July.  The amount of gross code in our implementation just to support this
case is very large, especially considering the very small benefit it gives
us.  Talking to the developers at Mozilla, it sounds like they have a
similar cost in code complexity.  I'm guessing every ICE stack does.  We
could clean up a lot of code complexity in a lot of code bases by requiring
rtcp-mux.


So here's my proposal:  make RtcpMuxPolicy == "required" be not only the
default, but the only RtcpMuxPolicy available.   All rtcweb endpoints must
support rtcp-mux.   An rtcweb endpoint would be free to fail if the remote
endpoint does not support rtcp-mux.



The whole reason we didn't do this before was because we wanted to work
with legacy equipment.  But Cullen's claim is that there is no legacy
equipment that can speak ICE (and DTLS) but not rtcp-mux.

So is there any remaining reason that we cannot require rtcp-mux?