| dc.description.abstract | Flourishing development of the Internet, following Internet users and multimedia services are increased so fast, for instance, Voice over IP, multimedia services and video conferencing, etc. Each of them has a set of criterion on session establishment of multimedia services in the past. Now 3GPP (Third Generation Partnership Project) chooses SIP (Session Initiation Protocol ) as signaling protocol while setting up sessions for multimedia services, hence SIP which can be used to set up Multiparty Multimedia Communications is the most attractive and discussing. As well as multimedia services are popularized, security issues are more and more important, and researches about security are in progress. Lawful interception is one of the most important topics.
To the aspect of lawful interception, has had multiple researches in progress or defined out specifications already, among them the lawful interception of Public Switched Telephone Network has been conducted for many years. With rapid developments of internet multimedia services in recent years, it is more difficult to use traditional methods on monitoring such services. So a thesis proposes the lawful interception system to intercept and collect various forms of communications while using SIP as signaling protocol, and mentions four kinds of interception strategies and structure in the thesis, and analyzes the pluses and minuses of every strategy. As the result of strategy analysis, choose a decentralized lawful interception strategy named Decentralized Interception on Proxy Server to implement. The decentralized architecture of storage and interception reduces the impact of all interception system when network situation is unstable or faults occur. Finally, analyze and prove the performance of proposed decentralized lawful interception system. | en_US |