Research And Design Of The Distributed Vod Video Server

The internet has grown rapidly in recent years. The bandwidth of the network, both bone network and the local access network, is becoming larger and larger, which provide necessary infrastructure for broadband applications. More and more people prefer to access information interactively. All of these create excellent condition for the development of the VOD technology.Video on demand (VOD), with the Video Server (VS) storing the video programs and other multimedia information, provides the clients with interactive video service through the transmission network and Consumer Premises Equipment (CPE). Of all the parts, VS is the core of the VOD, its stability and performance decided the performance of the whole system. There are some problems in current VOD systems: the volume is limited, once the volume reaches its limitation, VOD systems can't provide service for new request; lack of load balance; poor failure recovery.This paper made a deep research of the key technology in the VS design and tried to use a distributed architecture to make the common PC a Video Server with scalability, load balance, high availability and high performance. This thesis draw many improved approaches in the request scheduling, load balance, caching strategy, which are based on the deep analysis of these fields and the understanding of the video service characteristic. For request scheduling, the mixed scheduling and the partly batching algorithm were addressed, and the concept of subsection multicast was introduced. For load balance, a balance algorithm based on load prediction was discussed in detail. For caching strategy, we enhanced the LFU algorithm and introduce a solution based on frequency prediction. In addition, this paper designed a distributed architecture of VOD Server, and gave a full implement based on this design.