Hi All, I have a scenario, where the REFER to an INVITE is received before the ACK. There is a Desk Phone and a Call server. The call is initiated by the Call server.
Desk Phone <-- INVITE <-- Call Server Desk Phone --> 180 Ringing -->Call Server Desk Phone --> 200 OK/SDP --> Call Server Desk Phone <-- REFER <-- Call Server Desk Phone <-- ACK/SDP <-- Call Server The dialogue becomes confirmed when ACK is received. But in this case, the REFER is received before ACK and hence it is received even before the dialogue is confirmed. If, in place of REFER, a RE-INVITE is received (before ACK), then the Desk Phone should send 491 Request Pending, informing the server that a previous request is still being processed. According to RFC3515, the server should retry REFER (in case the response is any one of the below) Retry-After 404,413,480,486 o Retry-After 500,503 o Retry-After 600,603 o I have changed the code in Desk Phone, so that, when a REFER is received before the ACK is received, the Desk Phone responds with 603 Declined. The server should understand this 603 response and try to resend REFER after some time so that REFER is received after ACK. Is my approach okay in terms of RFC compatibility and implementation point of view? Please give your views. Regards, Karthik ::DISCLAIMER:: -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- The contents of this e-mail and any attachment(s) are confidential and intended for the named recipient(s) only. E-mail transmission is not guaranteed to be secure or error-free as information could be intercepted, corrupted, lost, destroyed, arrive late or incomplete, or may contain viruses in transmission. The e mail and its contents (with or without referred errors) shall therefore not attach any liability on the originator or HCL or its affiliates. Views or opinions, if any, presented in this email are solely those of the author and may not necessarily reflect the views or opinions of HCL or its affiliates. Any form of reproduction, dissemination, copying, disclosure, modification, distribution and / or publication of this message without the prior written consent of authorized representative of HCL is strictly prohibited. If you have received this email in error please delete it and notify the sender immediately. Before opening any email and/or attachments, please check them for viruses and other defects. -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
