[ibc]

This is RTP not WebSocket or HTTP. Media servers need a separate port for each RTP communication. A hack could be done to make all WebRTC endpoints to use a single port in mediasoup side. However mediasoup also support plain RTP endpoints and, in those, you need to be ready to listen for RTP from any remote IP:port (you don't know it in advance due to NATs). In WebRTC we can use ICE user/pwd (previously given to the server via signaling) but that's not possible with plain/regular RTP (no ICE).

[supermatt]

Isn’t that what the SSRC is for? I.e you use the SSRC (sent as part of media in the SDP) to identify the stream, rather than trusting an authentic stream is the only one to send to an open port? At least, that is how I understood the (multiple) rfcs. Not an expert here by any means.

[ibc]

In WebRTC spec (although not super mandatory but the current way to go), the client no longer signals its sending SSRCs into the SDP but a MID and optional RID values (if simulcast is in use), and those MID and RID are not supposed to be unique across all participants (not at all, but neither SSRCs are supposed to). Those MID and RID values are signaled in the SDP and then included into RTP packets as header extensions. The remote matches RTP packets based on them and then learns the associated SSRC for a faster lookup for future packets.

Anyway, WebRTC is not just about RTP. In fact, before RTP happens, ICE and DTLS must de done.

[supermatt]

Many Thanks. Sorry to be a bother :) Ill have a play around and see what I can get working for my usecase.