Below are my thoughts Regards,
Indresh K Singh On 5/23/07, Ivar <[EMAIL PROTECTED]> wrote: > > Hi, > > After reading rfc multiple times i can't fugure out following: > If UAC dialog gets 2xx for INVITE, it waits 64 * T1 for 2xx > retransmissions and send ACK to it. > Does that mean UAC dialog may not send re-INVITE during that time ? It can send a re-INVITE as the session is established at this point of time and a re-INVITE/UPDATE can be used to modify the session. 64* t1 timer is being run to ensure that for any reason if there is a retransmission of 2xx ( for example UAS send 2xx, but got no response, UAC sent the ACK for first 2xx, but UAS has not received the ACK and it retransmitted another 2xx. Now the first ACK sent by UAC may get lost in the network, so for the second one the if the UAC does not respond with an ACK. UAS will not be able to stop retransmission of his 2xx. > Or if it's allowed, what happens to timer ? After the expiry of 64 * t1 timer expiry on the UAC, retransmission related resources can be freed in the TU/UAC core and UAC will not be responsible for sending ACK for any 2xx response recieved afterwards ( could be possible bcoz of network delays etc ) And similar reverse version: > UAC dialog waits 2xx retransmissions, UAC dialog waits for first 2xx response and sends an ACK. After this if it receives a re-INVITE it should process it and not respond with 491 and should separately handle the 2xx retransmission on the previous INVITE-2xx transaction. Similarly on the UAS side if UAS has sent a 2xx response or retransmitted 2xx response and has received an ACK for a 2xx response, then it can send/receive a re-INVITE on a separate transaction and if it recieves an ACK on previous INVITE for next 64 * t1 second it should process it successfully. but UAS dialog send re-INVITE, is > it allowed(just kill wait timer) or "491 Request Pending" must be sent. > _______________________________________________ > Sip-implementors mailing list > [email protected] > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors > _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
