Hi, With your Diagrammatic view, it is clear that proxy knows where user C is and when user A sends an invite; proxy intercepts and intern sends an invite to user C with user A media capabilities. If proxy does receive a 200 ok from user C it just forwards the message to user A. (User C is complaint with user A media capabilities). If this doesn't happen user C proposes its own media capabilities and codec negotiation can take place (Proxy may intercept with each or ip phones may have the intelligence to carry out msg transfers without proxy in-between.)
Regards, Guru -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Wednesday, November 03, 2004 9:50 AM To: [EMAIL PROTECTED] Subject: [Sip-implementors] Codec negotiation Hi, When codec negotiation is taking place, - Since the endpoint terminals - usually IP phones - are not aware of the network configuration, How can the endpoint terminal (usually IP Phone) decide one of its codec capabilities ? For example, there're 3 users on the network. user A (IP phone, G.711, G.729 are possible, network 1.0.0.0) user B (IP phone, G.711, G.729 are possible, network 1.0.0.0) user C (IP phone, G.711, G.729 are possible, network 3.0.0.0) Proxy Server (network 1.0.0.0) A ----- B (same network, LAN) \ P | | C (different network, WAN) In case when the call between A and C is taking place and when the bandwidth is concerned, How would they know that G.729 should be used instead of G.711 because they're not in the LAN environment ? Thanks /Jun _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors Confidentiality Notice The information contained in this electronic message and any attachments to this message are intended for the exclusive use of the addressee(s) and may contain confidential or privileged information. If you are not the intended recipient, please notify the sender at Wipro or [EMAIL PROTECTED] immediately and destroy all copies of this message and any attachments. _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
