Research Of Content Distribution Mechanism In The P2P Network

With the development of network technology, Internet has become the most important content distribution system in the information society, but the traditional server-centric content distribution mode is also confronted with performance bottle neck. At the same time, P2P computing as a new mode of utilizing distributed computing resources comes into being. It is different from Client/Server computing, commonly there is no special server in P2P network and nodes can communicate and collaborate directly with each other. P2P computing can utilize increasingly unused resources in the edge of the Internet. Content distribution and sharing is one of the main applications of P2P computing, P2P-based content distribution system can fully utilize resources of vast clients and lighten the load of application server.The core of the P2P-based content distribution mechanism is the load balance arithmetic and the file's part choosing arithmetic. The purpose of the load balance arithmetic is to choose the node which is nearer or has a better performance as the distribution server. To adapt to the momentarily changing of the state and the performance of the nodes, the priority-based load balance arithmetic is used, whose principle is: calculating and sorting the priority by the states of the CPU and memory, the logic distance of the nodes and the states of network, then send a resource request to the node that has the highest priority. Like the principle of the file's partition, the file's part choosing arithmetic is divided into two: the Part-choosing arithmetic and the Block-choosing arithmetic. The Part-choosing arithmetic is priority-based: calculating and sorting every Part's priority by the situation of the Part in the nodes and the finish percentage, then sending the Part that has biggest priority. The Block-choosing arithmetic's principle is choosing in the order and the node's feedback: In the normal condition choosing the Block in the order; otherwise, choosing the Block beginning with the feedback.The load-balance arithmetic could make the download-node to send the resource request to the upload-node which is nearer and has better performance; the file's part choosing arithmetic is good for making the difference of the file's Part in the download-nodes bigger, and making the speed of the distribution faster. The content distribution mechanism whose core is the two arithmetics can make the node to get the resource faster from the nearer and better performance nodes.