180 with SDP followed by 200 OK with SDP

Joined: Tue 01 of Jul, 2008

180 with SDP followed by 200 OK with SDP

Posted:Fri 06 of Aug, 2010 (21:21 UTC)
I have a situation in which my UAC does not ACK the 200 OK from the UAS. The UAS sends a 183 with SDP, a 180 with SDP and finally a 200 OK with SDP.

As I understand the spec, the SDP for the 180 should be used by the UAC and the other two ignored. The caveat being that the SDP in the 200 OK must be identical to that of the 180. Is that correct?

I find that the Session Version is incrementing by one for the 183, 180 and the 200 OK. I believe this is incorrect. I believe even this should remain static. Is that correct? I’ve tried 3 different SIP endpoints; none of which will ACK the 200 OK. The SIP dialog is consistent. Wireshark confirms this, so I’m down to comparing the SDP of the packets. Thanks.