[SR-Users] rtpengine flags UDP/TLS/RTP/SAVP and UDP/TLS/RTP/SAVPF

[Juha Heinanen]

Richard Fuchs writes:

> You only need to specify the transport protocol in an answer if you want
> to change it from whatever the offering client sent (for whatever
> reason). If you don't specify the protocol in the answer (and you
> essentially did that as your flag wasn't understood and ignored), it
> will reply with the same protocol that the offering client used, which
> is normally what you want.

nice to hear. it simplifies my kamailio config a bit.

> FTR, RFC 5764 states that "UDP/TLS/..." must be used when DTLS-SRTP is
> used, only WebRTC doesn't seem to honour that and omits this prefix,
> possibly because SDES exists (or used to exist) as an alternative to
> DTLS-SRTP within WebRTC. Which actually makes me wonder if WebRTC
> clients actually understand the UDP/TLS/... protocols...

based on my tests, jssip at least does not understand UDP/TLS/..., which
is causing trouble.  in order to make the mess bigger, looks like sdp
will be dropped from next generation webrtc altogether (see
http://ortc.org).  this makes me wonder if it makes sense at all to try
to support webrtc clients in a sip proxy.

-- juha