Solution Of VOD System Based-on Limited Bandwidth

VOD(Video on demand) is a kind of technology which is used to search multimedia information in bandwidth and real-time environment .Most of it is small-scale products and a little products like NCVB and IBM can be transplant to MPP or centralized super computer systems.The pitfalls of this kind is : only can be used in special hardwares,cost of these is very high,most of these is based on centralized environment and broadcast center need very high backbone network bandwidth.We proposed a new distributed technology which design a super scale VOD through forsecast programes which will be demanded.Firstly, we propose a distributed VOD model, which is composed of programe center,order center and delegate,to satisfy the application demand of large-scale,many users and many programes.We reduce the bandwidth of prime network through most users' demand is accomplished in local and put order center to end of network.At the same time we reduce memory of the system through efficient programes cache policies whick only cache high frequency ordered programes .And the model can be flexibily extened.Secondly,because order center need to server many user and generally exceed the capability of server,so how to co-operate with different severs and implement load-balance between different severs is very important.We propse many co-operate methods and particularly introduce every method's theory and correlational algorithms.Third,video servers in different VOD systems store and switch programes in term of programes' order frequency.Because order frequency is changed with time,so switch programes based on forecast can optimize capability of the system.We discuss forecast of order frequency about programes' storage and switch of distributed servers.Lastly: According to the VOD program of Hunan Economic TV, the main research of the thesis was verified. Through cooperating among several servers, we can realize the balance loading of those servers,. And the result of predict analysis of the trend of VOD will be verified in the program...