----- Original Message ----- From: "Vijay K. Gurbani" <[EMAIL PROTECTED]>
> alok khemka wrote: > > > in sip when there are proxie server/s involved in forwarding the invite > > message the acknowledge traverses the same path the invite came from. > > > Only is *all* the intervening proxies Record-Routed. Otherwise, the ACK > may take a different route. There may be some confusion with the term "acknowlegement". The "responses" to the request do traverse the same path (by following the path in the Via headers). The SIP ACK message, which is an acknowledgement from the requestor/caller that it has received the response, will follow the Record-Route path contained in the response plus the last hop being the Contact header in the response. > > > what are the pitfalls of sending the acknowledgment directly to the > > caller??? (callee know the ip address of the caller by now!!!) > > > There aren't any pitfalls, per se. SIP supports either of the modes. > There may be certain services which require all signaling information to > pass through the service elements. Besides the requirement that the appropriate path (Via for resonponses and Record-Route+Contact for the ACK) be followed, the problem is that the intervening proxies will have state about the transaction. The messages must traverse the path so that the proxies can cleanup the state. cheers, (-:bob _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
