Research On Data Storing And Sharing Mechanism In Video-on-Demand Based Peer-to-Peer

Comparing with live streaming systems on peer to peer, VoD(Video-on-Demand) system faces more complex problems for the highly interactive and the data request difference features. How to improve the whole system's data service capability for clients is the key point in the VoD system based on peer to peer network. A new data storing and sharing mechanism for VoD system based on peer to peer network has been proposed based on the analysis of current live streaming and VoD systems. In VoD system, this mechanism provides a stable and efficient data service of data source server and improves the system data service capability through data share based on peer to peer network.The mechanism consists of two parts: data service of data source server and data store and share between clients in the peer to peer network. The data service of data source server includes raw streaming media data parse step and service client request step. The data store and share between clients includes four parts: the client data store; the maintenance of data store state in peer to peer network; data store optimization of the whole system; data transmit process between clients. The mechanism in this paper is designed to make full use of terminal clients'data store capacity and share data between clients in peer to peer network, and reduce improve the data service capacity of the whole system.The mechanism and relevant module have been implemented in an actual VoD system called GridCast. GridCast have been widely used for about one year. The analysis of the collected data shows that the data source server can service more than 250 clients, and the shared data of same clients have been over 50% of the total data request.