On Thu, 2008-12-11 at 13:38 -0500, Arjun Nair wrote: > Hi, > > Are we required to maintain backward compatibly with RFC 2543 when > dialog-matching? I.e. for example, if we don't find a from tag in a > request, can we just compare the whole from field instead? > > I am looking through 3261, and it does mention maintaining some > backwards compatibility with 2543 (i.e. an UAS should be prepared to > accept a request without a From tag). But, I didn't come across > anything regarding backward compatibly in dialog matching (which seems > kind of weird, since you can accept requests without tags). On top of > that, section 15.1.2 says > > Section 15.1.2 > > A UAS first processes the BYE request according to the general UAS > processing described in Section 8.2. A UAS core receiving a BYE > request checks if it matches an existing dialog. If the BYE does not > match an existing dialog, the UAS core SHOULD generate a 481 > (Call/Transaction Does Not Exist) response and pass that to the > server transaction. > > This rule means that a BYE sent without tags by a UAC will be > rejected. This is a change from RFC 2543, which allowed BYE > without tags.
Looking at 3261 and 2543, I think the point is that in 2543, both from- and to-tags are optional, but people rapidly learned that the UAS needs to provide a to-tag to allow forking to be handled correctly. So I think the "compatibility with 2543" point is that the from-tag may be missing, but that to-tag processing will be as we expect from 3261. > if we don't find a from tag in a request, can we just compare the > whole from field instead? That seems to be the correct thing to do. Dale _______________________________________________ sipx-dev mailing list [email protected] List Archive: http://list.sipfoundry.org/archive/sipx-dev Unsubscribe: http://list.sipfoundry.org/mailman/listinfo/sipx-dev
