I'm not sure I understand what you're asking. The scenario you describe is a little short on details. Assuming that you're not using preconditions (which would limit when the UAS can send 180 Ringing), and assuming that the UAC sent 100rel in the Supported header (which gives the UAS the option of sending 180 Ringing reliably or unreliably), then I don't see anything wrong with the scenario your scenario. It may be unusual, but it doesn't seem to include any protocol error.
The UAS may have sent the 183 Session Progress reliably and the 180 Ringing unreliably in short succession. Or it may have sent the 183 Session Progress reliably, received the PRACK, and sent the 180 Ringing and 200 OK to PRACK in short succession. The 200 OK to PRACK may have been delayed or dropped. At any rate, the UAC should process the 180 Ringing as it normally would. It should continue to wait for 200 OK to PRACK. -- Gary Cote www.awardsolutions.com _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
