________________________________________ From: [email protected] [[email protected]] On Behalf Of Nitin Kapoor [[email protected]]
I have one call scenario where my termination is sending the SDP in 183 as well as in 200 OK also. As far as i know if we are getting SDP in 183 session progress then my UAC can ignore the SDP in 200 OK. Also most of the time SDP is same. But here i noticed the slight difference of "Session Version". Here when my termination is sending 188 Session Progress with SDP is sending the SDP as below. I can see that my Termination is incrementing "*Session Version*" for SDP in 183 & 200 OK in same dialog.. _______________________________________________ (It would help if you gave the actual SDP rather than the SDP as decoded by some unknown program.) If the 183 and the 200 have different to-tags, then they are within different dialogs, and there is no constraint on the relationship between them. If the 183 and the 200 have the same to-tag, and the 183 is sent with PRACK, then the 183 finishes the offer/answer negotiation, and the 200 is allowed to be part of a new offer/answer negotiation. But the details of that are complicated, so you should consult RFCs 3264, 3262, 4317, and draft-ietf-sipping-sip-offeranswer. If the 183 and the 200 have the same to-tag, and the 183 is not sent with PRACK, then the two are required to have the same SDP (and the recipient is required to ignore the SDP in the 200 (assuming it receives the 183 first)). If the UAC is changing the SDP o= line, then the two SDPs are not the same, and it is in error. This is specified in RFC 3264. Dale _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
