The Design And Implementation Of SIP Though NAT Which Integrated STUN And HTTP Proxy

As one of the most important protocol in next generation network, SIP protocol has been widely used in VoIP systems. The NAT and firewall technology was generally used in enterprise networks to solve the problem of insufficient public IP address and network security issues. Although NAT technology can solve the problem of shortage of IP address, but SIP protocol doesn’t have the ability to get SIP through NAT, so NAT technology has negative effect on the VoIP communications.Currently, all solutions of SIP through NAT have their own limitations, each of them has advantages and disadvantages. In this paper, a new solution of SIP through NAT was proposed which integrated STUN and Http proxy. Firstly, the type of network environment was classified by STUN technology. Then, specifically traversing solution process was proposed to get through different network environments, for cone NAT it got through combine with UDP hole punching technique, for the strict NAT it got through with the help of STUN Http proxy technology and UDP hole punching technique. This solution can cross through all types of NAT/firewall without upgrading the network devices.In order to allocate system resources reasonably, SIP server resource optimization scheme was presented in this paper. The regular pattern of the client terminal call request was calculated by the statistical data, and then the performance target in the current setting was calculated. The expectations target of system’s performance was set to calculated the appropriate number of thread,the results showed that the number of threads in each period is far less than the original system, which prove the scheme can optimize the allocation of resources. Moreover, system resources were real time optimized to get a high quality service at the peak system service.In practice, using wireshark to capture packet and SIPp to pressure test, the new solution of SIP through NAT works efficiently and steadily. Comparison with other solutions, this solution has better NAT/firewall traversal capabilities and more highly efficient allocation of resources.