RTP over TCP with single port

Question

I am creating media server using WebRTC for video conferencing. As you might know when a user connects to the server two ports will be opened on the server side. RTP and RTCP ports over TCP. Thus, media server will need wide-range of available ports. The case here is not about multiplexing RTP and RTCP ports.

Assume that the media server is behind firewall and ports are blocked so that cannot open wide-range of ports. For example, the media server will use 8080 for signalling and 443 for RTP/RTCP. All video traffic will flow into 443 on the server side.

Is that possible?

Answer 1

It is possible, and many media servers provide that feature. Wowza enables single port for WebRTC over TCP; Unreal Media Server enables single port for WebRTC over TCP and for WebRTC over UDP as well.

Technically, it's quite challenging to develop such a feature; especially for providing single port for WebRTC over UDP. You need to relay incoming WebRTC traffic, arriving to your single port, to internal endpoints of particular RTCPeerConnections in the server. Initial Stun requests carry information that helps you find the right context and map the external to internal.