Research And Design Of A VoIP System Based On Kademlia

With the rapid development of communitation technology and the popularity of the Internet, as one of a new service in Internet, VoIP has already gradually substituted for the traditional PSTN communication system, not only because the advantages of cheaper cost and high network resource utilization ratio, but also can realize the interactive real-time communication through further integrating multimedia information such as data, voice, image and so on. As an important communication protocol of soft-switch, SIP has become the dominating protocol in next-generation network on account of the characteristic of simpleness, flexibility and expansibility etc. It has been widely being used in the session control of VoIP services. Meanwhile, with the achievement in file sharing,distributed calculation, distributed storage and so on, P2P technology brought forward a huge challenge to the system that the center server in C/S model. As users rapid increasing, require that the system has larger storage, better bandwidth, shorter network delay, stronger service capability and better security. P2P network just resolve this problem with its character of no center server, distributed research, self-organiaze, high expansibility and fault tolerance.How to combine the advantage of SIP with P2P has become a warmer discussion. The SIP system is not a pure P2P network, although it designed according to the architecture of P2P, so some research has begun to try the model of the SIP from C/S to P2P. But so far, the industry has not yet reached a standard combination of P2P and SIP. We introduced the problem of how to effectively combine of P2P and SIP based on the study of SIP and P2P in this paper, and then designed and implementated a communication system based-on P2P architecture and SIP protocol. The main works of this article as the following:1. In order to get full use of high expansibility of SIP protocol in next generation network, we expanded and implemented this protocol base on the detailed analysis of SIP.2. We used a modified algorithm of Chord to optimize the P2P network, and the results of simulation shown that the modified algorithm had better security and search efficiency.3. With a view to the practical application, we analysis of the application prospects of the P2P-SIP system in the Internet network and the mobile communication network.4. The design of network telephone system of P2P-SIP network architecture model which base on Kademlia was proposed, its implementation and carry out specific analysis.