>>UA needs to know and publish its public IP address/port. this is true in some cases. If you are a standalone UA (not using a SIP server) and want to receive requests, then rport is not good enough. (but of course, you still need an external STUN server)
In other cases, a SIP server (with which the SIP UA is registered) will be on the "outside". In this case I believe the SIP server (which accepts the registrations) will remember which port was used for responses and will direct future requests there. This is how it works in rfc 5626 (Managing Client-Initiated Connections in SIP) for UDP SIP signalling. Regards Attila -----Original Message----- From: Vivek Batra [mailto:[email protected]] Sent: 24 November 2009 11:49 To: Attila Sipos Cc: [email protected]; [email protected] Subject: RE: [Sip-implementors] [RPort] Request to know unique use case ofrport Attila, [Attila] - "rport is a very simple mechanism without very low overhead for achieving simple NAT traversal without requiring a separate protocol such as STUN which requires a STUN client and STUN server" [Vivek] - Even rport is used, I think STUN mechanism will still be required since rport will help only in getting responses across NAT, whereas to receive further transaction request, UA needs to know and publish its public IP address/port. Best Regards, Vivek Batra _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
