> > >> Suppose a proxy forks a request from UAC to uas1, uas2, > >> and each returns a 18x, with tag u1 and u2 respectively, which are > >> forwarded, as is, to UAC, > >> and then uas1 returns a 486 with tag u1 and uas2 returns 500 with tag u2 > >> Proxy picks best response 486 to return to UAC. > >> > >> Question: > >> Will the TO tag in the 486 reponse be u1? Or, will there be no TO tag. > >> Is this implementation specific or does the protocol specify this > >anywhere? > >> > >Based on section 16.6 on bis-05, the tag received in the response is > >preserved when the selected response is forwarded to the UAC. Therefore, it > >would be u1 for your example. The proxy is not allowed to modify the To > >header in the forwarded response. > > A 2xx response is the only type of response that is truly "forwarded" by the > proxy. Any non-2xx response is really hop by hop. Therefore, in your > example, the proxy will add its own To tag when it responds to the UAC. > Niether u1 or u2 would be used.
Section 16.6 of bis-05 explicitly forbids the proxy from adding its own tag. It is not a UAS in this case. The proxy is suppose to select the best response from the ones it has received and forward that response to the UAC. _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
