Study Of Cooperative Caching Scheme For Unstructured Peer-to-Peer Network

In recent years,Peer-to-Peer Network(referred to as P2P)systems has caused great concern,especially that it can provide file-sharing applications,and distributed computing and Internet-based phone has been successfully achieved. In these applications,concept of P2P is mainly used in file-sharing applications that the exchange of media data,such as music,movies,and procedures.There are two kinds of P2P file-sharing application,the structured and the unstructured.Unstructured P2P networks have power-law topology, and the number of content requests also follows power-law distributions. These properties cause two problems:the high-load of high-degree peers and the quick deletion of rarely requested contents. We propose a new caching scheme——MCU(Most Currently used) that replaces the cache on the basis of the number of request messages per unit of time. The scheme of algorithm aim to achieve the high-degree peers to delete the popular contents and low-degree ones hold the unpopular contents by setting the threshold properly. It significantly reduces the load of high-degree peers and improves the hit rate.Moreover,we use a simulation to show the effectivity of our proposed method. The MCU scheme and LRU,LFU and ARP scheme comparison,to prove that the advantage of the new replacement policy in load balance and hit rate.Finally, the paper demonstrates the deficiencies of the proposed scheme, and future work is prospected.