Does webrtc-SCTP rely on UDP?

[huixue]

From the dep graph here:
https://webrtc.rs/res/webrtc_stack.png

I guess webrtc-SCTP in this implementation relies on UDP to work? However it conceptually should not be this way, where SCTP could just run on top of IP.

[huixue]

I'm asking, because I'm using webrtc/sctp/examples/pong.rs, and use another SCTP client trying to connect to the server, but because pong.rs is listening on UDP, the SCTP client couldn't connect to it.

[k0nserv]

Yes, in webrtc-rs SCTP runs on top of the ICE transport which is either UDP or TCP(in the case of TURN being used).

That said, this is abstracted away from the SCTP implementation itself via the Conn trait from the webrtc-util crate. It might be possible to implement a Conn directly over ip to avoid UDP and TCP if you wish