The Research On Key Techniques For The P2P-based VOD System

With the development of Internet,Video-On-Demand(VOD)has become one of the main applications,which greatly changes the traditional TV-waching pattern.The increasing of subscribers and video arises new chanllenges to the current VOD system.How to optimize the performance of current VOD system is the new problem of Internet content providers.Currently,for the VOD system the Content Delivery Network(CDN)and Peer-to-Peer(P2P)are used.The CDN has the disadvantages such as poor scalability and high cost of construction and operation.P2 P has the advantages of low cost and good scalability,but the Quality of Service(QoS)is not stable.How to optimize the performance of P2 P system to build a better VOD system combining with CDN has become the problem concerned by the Internet content provider.In order to solve the above problems,in this thesis a P2P-VOD system is designed,which divides the P2P-VOD system into functional layers horizontally and autonomous domains vertically.It has the ability of CDN-VOD system,while it does not need to change the CDN-VOD greatly.In addition,this solution can also effectively control the traffic in the P2P-VOD system,guarantee the QoS while the scale of subscribers increases.As the peers in the P2P-VOD system are free to leave the network,there is significant difference between peers in terms of the performance and the network conditions.Therein,how to select and manage the peers affects the QoS.To combat it,in this thesis an adaptive neighbour selection strategy(ANSS)is proposed to improve the probability to be selected while improve the performance by introducing the neighbour updating scheme and the handover scheme.Experimental results show that ANSS can significantly improve the service capability of peers and the bandwidth utilization.For the new or popular resources in the P2 P network,there are few peers that own these resources,which results in decreasing of QoS.To combat it,a resource Pre-Delivery Strategy(PDS)is proposed in this thesis.It improves the resource distribution by pre-downloading the scarce resource.Experimental results show that this scheme can effectively reduce the boot delay of the popular video and the service rejection rate while improving the system throughput.Finally,the architecture of P2P-VOD system is presented including the detailed design of related network elements to verify the above solutions,including the system and static structure represented by the class diagram.