A New Tunnel Scheme for Multimedia Communications Traversing NAT/Firewall in NGN

A new tunnel scheme for multimedia traversing NAT/Firewall in NGN (next generation network) is presented, which is improved on the basis of MASMCT (Multi-agent System for Multimedia Communications Traversing NAT/Firewall). In this new scheme, we move the controlling agent into private network and incorporate the function of signaling agent in public network into the Softswitch, but we still keep the multiagent architecture. The design can not only speed up the call signaling process but also offer the controlling agent component with protection provided by the firewall. Finally, the performance evaluation of the system is also given based on SIP protocol and G.723.1 coding standard.