> I have call flow like where Vendor sends > 183 w/SDP included Rseq and customer sents > the PRACK and 200 OK from vendor. > > After that vendor is again sending 1~2 > 183 w/SDP where it is not changing anything > in SDP but only asking for PRACK by sending RSEQ. > I checked the RFC , but cannot see anything like > which says UAS cannot send multiple 183 w/SDP.
Concerning the additional 18x messages, I assume that To tags did not change and that the RSeq value was incremented. > Can you please help on this, whether any UAS can > send multiple 183 w/SDP where it is asking for PRACK? > Is it valid call flow, because i cannot see > anything RFC. RFC 6337 section 3.1.1 indicates the following (F9 is second 18x when prior 18x contained answer SDP): "The UAS does not include SDP in responses F9 and F12. However, the UAC should prepare to receive SDP bodies in F9 and/or F12, and just ignore them, to handle a peer that does not conform to the recommended implementation." _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
