Research On Layered Streaming Media System Based On P2P And CDN Technology And The Key Problems

Multimedia information has already become the most important transmission content in the network, so with unique technological advantages, streaming media is widely used. At present, the main streaming media systems are based on P2P technology and CDN technology. P2P has the advantage of low extended cost. CDN has the characteristic of content copyright management, effectiveness of users management, supportability of QoS and flow orderliness.Therefore, this paper proposes a layered streaming media system which integrates the above two technologies, and analyzes the structure and the working process of the system. The three layer construction of the system includes the source server layer, the proxy server layer and the client peer layer. During working, the system experiences three stages: CDN, CDN/P2P and P2P.On this basis, this paper analyzes the two key problems of the layered streaming media system, load balancing and congestion control algorithms. It gives the load balancing strategies of the system, including the global load balancing strategy and the local load balancing strategy, and implements them based on JXTA platform from the following aspects: establishing peer groups and addition, obtaining service, withdrawing of the peers. Furthermore, based on the Feedback Congestion Algorithm(FCA), this paper presents an improved algorithm(IFCA) on feedback real-time performance and parameter adjusting. Results of the simulative test based on NS2 show that the proposed method, by which jitter and throughput are improved, and also keeps TCP-friendliness.