Research And Simulation Of Large-Scale Streaming Distribution System

With the development of Internet and multimedia technology, people are more andmore convenient to access all kinds of information. As an important application, theVideo-on-Demand streaming system, providing people audio and video services withshort waiting time, small cache and supporting for user-interactive operation, has beenwidely used. Benefit from the development of broadband networks, the VoD systemfor large-scale users will have broad application prospects.There are some schemes for content distribution. The scalability of C/S mode islow because, as the scale increase, the central server can easily become the bottleneckof the system. IP multicast technology allows s single packet sent to multiplerecipients and has better scalability. However, it has not been a large-scaledeployment due to several fundamental concerns. At present, CDN technology andP2P technology are the two main distribution technologies for large-scale VoDstreaming system. The CDN technology reduces the load of the central server bypushing content to the cache servers in the edge of network. When the number ofusers rises sharply, the server equipment must be increasing linearly to ensure thequality of service. By taking advantage of the decentralized computing resources ofnodes in the network, P2P technology makes the entire system load decentralized. Ithas high scalability and its cost is low.The content of the research is to provide streaming media services for large-scaleusers, by focusing on system scalability, robustness and adaptability. By combiningthe advantages of CDN and P2P technology, this thesis designed a VoD streamingsystem by the CDN-P2P architecture. The following aspects are the focus:(1) Between the core streaming media servers, CDN is used to design the contentdistribution model. And the edge cache servers, whose load balancing is directed bySN server, are divided into multiple regions.(2) Drawing on the BitTorrent framework on user layer, the thesis uses a central server to manage files index and peer joining and exiting, and to guide the peers toestablish partnership between each other.(3) Considering the factor of the user behavior for VoD system, the thesis studiedsome classic user behavior model, and designed a user playing model based on theinteractive operation.(4) Proposed a peer select mechanism based on the peer online time and distancebetween nodes in the network. The simulation result show that, compared withrandom selection mechanism, the proposed mechanism has not only effectivelyreduced traffic on the backbone between networks but also reduces the videoplayback start delay, and improves playback continuity.