SCTP and webrtc

问题:

I saw that SCTP is going to be used for Data Channels starting in Chrome 31, and officially RTP based channels are going to be deprecated sometimes in February 2014 according to this google group thread:

https://groups.google.com/forum/#!topic/discuss-webrtc/y2A97iCByTU

Does this also mean that webrtc audio and video channels are also going to be transported over SCTP eventually(if not already in the works)?

How does RTP fit in the whole SCTP transport effort? Does that mean SRTP packets will flow over SCTP data channel? Or perhaps just the payload will be sent over SCTP transport protocol.

If I am reading info on SCTP, it combines best of TCP and UDP protocols; but it does not include encryption by default; so in mind the traffic flowing over should still be encrypted.

Any additional info would be helpful. Thanks!

回答1:

The audio and video will keep going over RTP (actually SRTP which is the secure version or RTP) but the data channel will uses SCTP over DTLS over UDP. Both Firefox and Chrome are implementing this and you can find it described in the IETF draft specifications. For some types of NAT / Firewall traversal, the UDP packets may get tunneled in TURN over TCP.

Glad to provide you pointers to the draft specifications if that helps.