> Is it acceptable for a UA to merely use the presence of a branch > parameter in the VIA to distinguish a request as having been > received from a proxy instead of from another UA.
I would see this as bogus. I can see no reason why a UA might not logically combine the roles of UAC and proxy, and fork, for instance; in which case it would have to weave branch magic. > I am also interested in determining whether all parameters in a > VIA need to be used or just the branch alone will do to > distinguish one proxy from another, in the case of a merged > request at the UA. I would consider it unlikely that you would get branch collisions from different proxies; however, I am struggling to find anything in bis-05 &:) that actually mandates this. In any case, for robustness, it would seem wise to always inspect the topmost Via's "sent-by" when involved in such procedures. (I might note that this would seem to be a slight augmentation of step 2 of Section 13.3.1.) > Finally, is the branch a mandatory parameter when a proxy adds > a VIA to the request? Neither the rfc nor the bis-04 specify > this explicitly. But they seem to strongly imply this. For > example, bis04 states in 10.46.6 Syntax > [The "branch" parameter is included by every proxy.] The branch parameter is mandatory. See step 3 of Section 16.5. (It was also mandatory as viewed by bis-04; see section 17.3.1.) - Jo. _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
