Hi, In second case (UDP), UA1 registers with proxy/registrar, assuming they have same ip:port, a mapping is done by the symmetric NAT for only UA1 to Proxy/registrar communication. 'received' and 'rport' tags tell the proxy, from which ip:port this msg was sent and proxy should send reply to same address. So in this case signalling with go smoothly. Problem comes in the establishment of media path.
Vivek ________________________________ From: [EMAIL PROTECTED] on behalf of Joseph Cheri Sent: Wed 03/08/2005 06:23 AM To: [email protected] Subject: [Sip-implementors] Query regarding NAT Hi All, I am currently going through the NAT Scenarios. I have a doubt regarding a NAT Scenario and would want to know what would be the solution for the same. The scenario is as follows :- UA1 ---> Symmetric NAT ---> Proxy/Registrar ----> UA2 The UA1 is in private domain. The Proxy/Registrar and UA2 are in public domain. There are two transports through which the UA1 can register with Proxy i.e. TCP and UDP. > If the UA1 registers with its private ip address and port which is a TCP > contact then the UA1 establishes a connection with the Proxy/Registrar using > the instance-id and flow-id. Now if the UA2 wants to contact UA1 then using > the instance-id and flow-id, the already opened connection is obtained and > the request is forwarded to UA1. > If the UA1 registers with its private ip address and port which is a UDP > contact. In this case there would be no connection establishment between UA1 > and Proxy/Registrar. Now if UA2 wants to contact UA1 using the private IP > address of UA1 then how does the UA2 request traverse through SYMMETRIC NAT, > as the UA1 contact is not reachable from the Proxy/Registrar ?? Thanx, Jose --------------------------------- Free antispam, antivirus and 1GB to save all your messages Only in Yahoo! Mail: http://in.mail.yahoo.com _______________________________________________ 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
