The Solution And Implement Of SIP Traversing NAT

VoIP(Voice over IP) includes a set of protocols and technologies such as SIP and H.323. It challenges the traditional communications with its powerful functions,cheap price and obvious facility.Not only voice is supported by VoIP,more services such as video,data and fax etc,is also supported. But unfortunately , there exist a great amount of NAT(Network Address Translation)applications, which has become the greatest obstacle on the development of VoIP.The main work of this dissertation is about how to use ICE to implement SIP traverse NAT. At first, it introduces the SIP protocol and the existing traversing methods.Then it analyzes the existing traversing methods, and finds that there is no one that supports traversing of service stream and control stream, and at the same time has the sufficient efficiency and extensibility. The best method is to abstract the best approaches among them and apply the right method to the most proper network environment. ICE (Interactive Connectivity Establishment) is adopted to fulfill this requirement.After that, it concludes the advantages and characteristic of ICE.Then it analyzes the basic components and interactive traversing processes. After that, it describes the fundamental and implementing architecture of the ICE.Also it does the system test, analyzes the test results and work out the solutions. At the end of this dissertation, it concludes the status of the system and the work need to do in the future based on the work which has been done.