Okay, what I said is a bit confusing. Well it is useful for device (sip phone) behind a NAT to receive calls from proxy. Assume phone is on private network and need to register with server on public network. You can do this with help of RFC 3581 which defines symmetric response routing and rport. When phone sends register request with rport it will force server to respond to same port it received request from. Since when request passed NAT device it created binding, NAT device will properly pass this response to the phone. Further, if contact header has public ip and port, all future calls will be properly send to public ip/port and if binding on NAT device is still alive forwarded to the phone.
Hope this helps, Nenad -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Iñaki Baz Castillo Sent: Thursday, July 24, 2008 4:53 PM To: [email protected] Subject: Re: [Sip-implementors] Is "received" and "rport" used in SIP TCP? El Jueves, 24 de Julio de 2008, Nenad Milidrag escribió: > Hi, > > I am pretty sure it is still useful in certain cases, for example, if you > have a NAT and NAT device is not SIP aware. Using rport/received together > with you can get your public ip/port seen by the proxy and when > reregistering provide your public ip/port to the proxy. By keeping your > connection to NAT device persistent incoming call from proxy should still > be properly routed. Also, in this case you should use symmetric sip. So "received"/"rport" is just ueful in the UAS (a registrar in this case) the transport layer to inform the core, is it? -- Iñaki Baz Castillo _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors --------------------------------------------------------------------------- This email communication may contain CONFIDENTIAL, PRIVILEGED and/or LEGALLY PROTECTED information and is intended only for the named recipient(s). Any unauthorized use, dissemination, copying or forwarding is strictly prohibited. If you are not the intended recipient and have received this email communication in error, please notify the sender immediately, delete it and destroy all copies of this email. --------------------------------------------------------------------------- _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
