Design And Implementation Of SIP Internet Phone Based On SCTP And DCCP

With the rapid development of computer and network technology, information network, especially the Internet, brings great changes in people's life. Internet phone becomes more and more popular, because people prefer to communicate with each other on the Internet. In this paper, DCCP and SCTP are introduced to the SIP internet phone to improve the performance of communication.Firstly, this paper analyses the disadvantages of the SIP internet phone on the basis of TCP and UDP in reliability, congestion control and security. And then, the theory of SIP and RTP are introduced as well as the characteristic of the SCTP and DCCP transport protocols.Then, this paper designs the SIP internet phone based on SCTP and DCCP. SCTP can ensure security, reliability and high efficiency in transporting SIP message, and DCCP can ensure fair use of the internet because of its congestion control in transporting RTP packet. Furthermore, this paper describes the signaling processing of our design.On the basis of design, this paper gives the implement of the SIP internet phone. It selects open source software of SIP user agent and SIP proxy server and gives the realization of these entities in order to make them support SCTP and DCCP.Lastly, this paper sets up the experimental environment and tests the process of SIP registration and dialog, including one proxy server and two proxy servers. The experimental results are analyzed. Such tests show that each part of design can basically satisfy the system design requirement.This solution had applied for China Invent Patent (No. 200710122011.7).