Abstract:

The SIP protocol based VolP and other IP multimedia application systems face challenges in traversing the Network Address Translator （NAT）. In this paper, we propose a STUN based solution to solving the problem. The implementation and performance evaluation of the solution are presented. The solution does not require the modification and extension of related protocols and NAT devices. It can work through NATs tandem. With this solution, users can successfully initiate a call to connect other users behind NAT. This solution has been adopted successfully in the wireless VolP Gateway based on the emb edded Linux platform, and it also can be applied to other SIP protocol based terminals.

Key words: （VoIP, SIP, NAT, STUN）