I would first examine the SDP. A valid scenario for this is if the SDP should change for some reason. We have a scenario similar to this where a Nextone receives multiple 1XX messages on the B side with different SDP information. It will then send it out to the A leg and the only difference is the version identifier in the SDP.
Ed On 07/21/2010 03:37 PM, WORLEY, Dale R (Dale) wrote: > ________________________________________ > From: [email protected] > [[email protected]] On Behalf Of Peter > > An incoming call is first ringing on a call center queue: > The UAS is sending a 180 Ringing with SDP and a require: 100rel, the UAC > responds with a PRACK and the UAS again with an 200 OK. > > Then the call is actually ringing on a UA (IP hardphone) > The UAS send a 180 Ringing again with an SDP and a require:100rel, but > the UAC ignores this as is seems a duplicate message. > > > <-- > INVITE/SDP supported: 100rel > > 100 Trying --> > > 180 Ringing/SDP --> > Require: 100rel RSeq:1 > <-- PRACK > > > 200 OK --> > > 180 Ringing/SDP --> > Require: 100rel RSeq:2 > > 180 Ringing/SDP --> > Require: 100rel RSeq:2 > _______________________________________________ > > I can't imagine why the UAS sends the 3rd and 4th 180 responses -- it has > already confirmed the dialog with the 200. I'm not sure if "late" > provisional responses are forbidden by any specification, but I would not be > surprised if the UAC does not pay any attention to them. > > Dale > > _______________________________________________ > Sip-implementors mailing list > [email protected] > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors > _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
