A final response to an INVITE is always ACKed. It doesn't matter what role the thing providing that final response plays - when a client sees a final response to an INVITE, its going to send an ACK.
Its not clear what you are trying to say with your Registar example. 1) Registrars will not return a 200 OK to an INVITE (if an element returns a 200 OK to an invite it is not acting as a Registrar). 2) Non-INVITE transactions don't utilize ACK. So a 200 OK to a REGISTER wouldn't get ACKed. If the above doesn't clear up your question, ask again with a little more detail. RjS On Thu, 2002-03-14 at 12:48, Radhika wrote: > Hello All, > > The content of the mail says that an ACK is sent for a 200 OK. But as > per my understanding, 200 OK is a final response and in case of say, a > Registrar, there is no ACK received by it, when it sends a 200 OK. > > Please correct me if I am wrong. > > Thanks and Regards, > Radhika. > > ----- Original Message ----- > From: Ramachandran Iyer <mailto:[EMAIL PROTECTED]> > To: [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> ; > [EMAIL PROTECTED] > <mailto:[EMAIL PROTECTED]> > Sent: Wednesday, March 13, 2002 10:00 PM > Subject: RE: [Sip-implementors] Via branch in ACK for 200? > > > hi, > > > I guess the question being asked here is more from a client perspective > > > of what an UAC is supposed to do while sending an ACK back.. for a > non-2xx final response... > > > As mentioned earlier, the spec makes it clear for an ACK being sent for > a non-2xx final response > > > as having to have the branch parameter in Via (17.1.1.3) same as that of > the INVITE request > > > as this ACK will belong to the same transaction. > > > But an ACK for 2xx final response, will be a new transaction in itself > and thus as per the spec should > > > have a unique branch parameter, which the UAC would need to construct. > But now again the UAS > > > does'nt really have to do anything about it as an ACK does'nt solicit a > response. So the branch may > > > not really be of any use. > > > Could we get some more clarity on this. > > > > Rama > > > > > Brett Tate <[EMAIL PROTECTED]> wrote: > > > > In ACK generated by client transaction for non-200 responses > > the bis clearly states that the topmost Via should be used > > when constructing the ACK request. What about the ACK > > generated for 200 OK? I guess that this kind of ACK should > > have a unique Via branch ( not matching the ACKed INVITE's > > branch) but I couldn't clearly derive it from bis. Could > > someone please clarify what is the correct behaviour ? > > After sending a 200 response, the UAS/proxy > cannot rely upon the branch being the > same because the prior proxy might not > have added itself to the record-route. > Thus it ultimately should not make a > difference either way. > > ATTACHMENT part 2 application/ms-tnef name=winmail.dat > > > > > _____ > > Do You Yahoo!? > Try FREE Yahoo! Mail - the world's greatest free email! > _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
