Research And Development Of P2P Multimedia Communications Based On SIP Protocol

With rapid promotion of personal computer performance and popularization of broadband network, a large number of customers'resources and network bandwidth are idle. Under such background, P2P model obtains people's widespread attention based on SIP Protocol, which becomes hot topic in the domestic and foreign field. This paper launches the work which centers on the SIP Protocol in the multimedia application. Reading and summarizing some literature material,the author proposes a new thought and a method,makes massive practice, and achieves certain progress in this research. With technologies related to SIP Protocol on the P2P multimedia communications, the paper does some exploratory work in the following two aspects:Firstly, in thoroughly understanding the promise of STUN working principle and process in the SIP the author proposes solutions of the traversing all type NAT. This paper makes profound analysis and research on existing many kinds of different technologies of the NAT traversing, and compares with the advantages and disadvantages. Finally, the paper mainly develops experiment and the confirmation about the working principle and process of STUN in the SIP. It proposes one method based on forecast Penetration Symmetric NAT solution (PSTN), which achieves uniform processing regarding all NAT.Secondly, the paper carries on the re-development and the encapsulation of open-source the SIP Protocol Stack. In comprehending the foundation of SIP principle and applying to an open-source SIP Protocol Stack, the paper reaches P2P multimedia communications software framework,including the Client and Server. Client consists of the registering, calling, hanging up, answering, voicing and messaging functions of SIP phone. The most important function of SIP Server is to provide the caller the receiver's location information,so that the two sides can call each other successfully,which can also realize the functions of caller verification,management,collection of call information and other functions.In the development, the system is divided into a number of modules. It introduces the function and implementation methods of each module.The test results of each module are given. Finally, the author analyses disadvantage and gives requirements in the future work.