Thank You very much for the response guys! What about the Call-ID? If the same UA sends the REGISTER requests with different cal-IDs, what would be the ideal response from the registrar? I know that RFC 3261 prohibits from doing this. If UA fails to use the same Call-ID, how will it effect the registrar in ordering the requests?
CoolGoose. On Mon, Feb 23, 2009 at 1:03 PM, Dale Worley <[email protected]> wrote: > On Mon, 2009-02-23 at 09:30 -0800, cool goose wrote: > > Can someone explain me the importance of CSeq in REGISTER request? RFC > 3261 > > specifies that UA must increment the CSeq value by one for each REGISTER > > request with the same Call-ID. What is the expected response from a > > registrar if a UA keeps retransmitting the REGISTER request with same > CSeq > > value and the same Call-ID? > > The registrar will keep a record for several minutes of the REGISTER > that it received and the response that it gave to the REGISTER. When it > receives a duplicate of the REGISTER, it will send a duplicate of the > response, without further processing. (This is necessary because the > Internet can duplicate UDP messages, and also to all the sender to > re-send if the response gets lost.) > > After the registrar has purged memory of the REGISTER (with that CSeq), > it will most likely respond to further REGISTERs with that CSeq will a > 500 "Out of order" response. > > Dale > > > _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
