Hi, in our SIP implementation, we have encountered a problem for which we don't find a clear statement in RFC 3261. We would like to hear your opinion about this issue, if possible.
Namely, we have sent a Re-Invite on an existing session and received 100 Trying reply. 100 Trying reply turned off Timer B. After 100 Trying, we haven't got any answer on Re-Invite. Chapter 14.1 of RFC 3261 says: "If a UA receives a non-2xx final response to a re-INVITE, the session parameters MUST remain unchanged, as if no re-INVITE had been issued. Note that, as stated in Section 12.2.1.2, if the non-2xx final response is a 481 (Call/Transaction Does Not Exist), or a 408 (Request Timeout), or no response at all is received for the re-INVITE (that is, a timeout is returned by the INVITE client transaction), the UAC will terminate the dialog." Quoted paragraph does not say anything for provisional responses. I find our implementation aligned with the RFC (quoted paragraph and Figure 5) but it is also evident that we can not keep waiting for the final response forever. My question is which timer should control the duration of INVITE transaction? Can Timer B me expanded and NOT switched off if provisional response is received (Figure 5) or it would be better to implement a new timer. If you think that a new timer is a better solution, can you suggest it's guiding value? Thank you in advance, Mia _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
