2008/8/22, V.S.R Kumar Kadimcherla <[EMAIL PROTECTED]>: > Hi all, > When a stateful proxy has received 302 responses from all the down stream > client transactions and received some contacts in those responses then proxy > is sending 300 response to the upstream by appending the all contacts > received in 302 responses in to the contact header field. Proxy is not > looking for any duplication of contacts before forwarding the 300 response. > Is it a valid behavior? > > Elimination of duplicate entries is duty of the proxy or end point has to > take care of this?
AFAIK, since the proxy is not doing recursion on the 3XX response (it doesn't generate new branches one for each unique Contact URI) it's task of the UAC doing it. Imagine a simpler example with a single 3XX response: - A calls B through a proxy. - B replies a 302 with: Contact: sip:[EMAIL PROTECTED], [EMAIL PROTECTED]@domain (C repeated). - If proxy doesn't do recursion on 3XX it makes no sense that proxy would "check" all the "Contact" values to delete duplicated entries. So proxy would just forward the 302 to A. - A will inspect the Contact values and decide which one to use (this implies removing duplications). Note that if the proxy should check the "Contact" to remove duplicated URI's it must perform complex URI comparisions (19.1.4), not good for performance. Better leaving that hard work for the poor UAC (A). -- Iñaki Baz Castillo <[EMAIL PROTECTED]> _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
