[Serusers] FW: Forking Proxy

Hi All Sorry about the last post - I have attached the call flow as an image this time :-) I have a question about the CORRECT operation of UA when making a call via a forking proxy: (see attached image for call flow) Lets say UA1 calls 7000(a)sip.com and user 7000(a)sip.com is available at UA2 and UA3 i.e. the Proxy forks the request. * UA1 is using the to-tag of the first 180 RINGING it received (frame 5) no matter what the to-tag in the 200 OK is * My question here is: who is in the wrong???? The proxy or UA1? * Should the proxy change the to-tag of the ACK before forewarding it to UA3??? Jason Penton Rhodes University Grahamstown South Africa