Hi, I would like to use two offer/answer cycles during session setup (without using UPDATE) and ask for feedback if the following sequence will work.
This is the sequence seen from UAC perspective. UAC Proxy --- INVITE SDP-1 ------------------> <-- 183 Session Progress SDP-2 ----- <-- 200 OK SDP-3 -------------------- --- ACK SDP-4 ----------------------> The point is that 200 OK carries a new SDP (SDP-3, the actual SDP of the Session Partner), while 183 carries the SDP-2 of an announcement. SDP-1 / SDP-2 is the first offer/answer SDP-3 / SDP-4 is the second offer/answer (expectation SDP-4 = SDP-1). >From my interpretation of RFC3264 the sequence could work. The Caller gets a special announcement before cut through. My doubts & questions are now: - Will UACs follow the change of SDP during session setup? - Will SDP-4 be identical to SDP-1? Who knows how UAs might behave? Cheers Franz _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
