Research, Realization And Implementation Of IP Multimedia Communication System Based On SIP

In recent years, the multi-media communications has always been a hot topic in both the communication and the Internet fields. Nowadays,with the development of our society,SIP and P2P technique have become the two most popular techniques in the IT field. The P2P system which has high reliability,high scalability and high fault tolerance brings a revolution of thought and calculation pattern to the whole IT world,and it subverts the traditional Client/Server mode from the root. Its influence areas cover the file-sharing, instant messaging, distributed storage, distributed computing, and streaming media,etc. While the SIP protocol is also becoming more and more popular both in the current Internet communication systems and IT industries because of its advantages such as simple, easy to extend, easy to realize.It is becoming the key protocol of NGN and 3G Multimedia Subsystem domain, and might become one of important protocols for communication system and signal controlling system in the near future.How to effectively combine both technologies and make use of their advantages has become a major hot spots, so many research institutes have carried out many beneficial researches and have a try in this area. However, so far, there is not any P2P-SIP technical specifications for IT industries. In this context, this paper will do an in-depth study, exploration and design a workable system of IP multimedia communications.The combination of SIP and P2P will run the SIP protocol in low cost.At the same time, SIP back-end server is no longer necessary.What's more,SIP request will be extended to low-end consumer market and help the Internet phone provider compete with Skype. Currently there are two main ways about the combination of SIP and P2P: the first method is to use SIP-using-P2P mode; the second one is P2P-using-SIP approach. This article is to mainly about the second approach.This paper firstly introduced the SIP protocol and the P2P technology, research and discussed the advantages and disadvantages of the two key technologies. Then,it analyzes the popular Skype Internet communications system in the current network.Based on the aboved mentioned, this paper designs our system of IP multimedia communications, and explains the system, including network topology, architecture design, the core algorithm, protocol level, message design, communication flow, etc.Finally, under the conditions of the permission, we test and apply our system.And the result of the test and application indicates that this solution is successful and practical. Then make a final summary and outlook.