> Now ideally UAC should wait for 200 OK for PRACK > from UAS , but before UAS reply with 200 OK for > PRACK, UAC sends the UPDATE method with/SDP and > my SBC forwarded SIP 500 on leg1 to UAC. So my > knowledge says UAC should not send UPDATE method > before getting the 200 OK for PRACK. > > Can you please let me know if my understanding > is correct on this?
The UPDATE can be sent before receiving the 2xx for the PRACK. However as you noticed, it might cause 500 response to be sent for UPDATE. And depending upon RFC 3262 interpretation, it might cause a 500 response to be returned for PRACK if UAS receives the UPDATE with higher cseq first. Thus to resolve your issue, you can either 1) queue the UPDATE and await PRACK's 2xx (or Timer F expiration), or 2) handle the UPDATE 500/491 response and resend with higher cseq later. If your PRACK contains an offer or answer, RFC 3311 section 5.1 and 5.2 may be of interest. _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
