Research On Network-aware Structured P2P Overlay Based On Small World

In recent years, P2P technology has become the hot spot in computer research. And the P2P overlay network, as P2P system's skeleton, has played a very important role in the P2P system's performance. The existing P2P overlay network can be divided into two types of unstructured one and structured one. The unstructured overlay network has characteristics of big cluster coefficient and great average network distance. And in structured overlay network, the cluster coefficient and average network distance are both small. At the same time, in the existing P2P network construction, the underlying network topology hasn't been taken into account. Thus, in peer-to-peer correspondence, the actual latency can actually be very large although the hops of path are just few.First, in view of existing problems of P2P overlay network, this article applies the small world theory and the idea of network topology information collection to propose a new P2P overlay network (NSWO network).and this new overlay network's construction algorithm has been given a detailed description in the paper. This overlay network has all Characteristics of network-aware, big cluster coefficient and small average network distance.Then, taking advantage of NSWO network's characteristics, we have developed a highly efficient algorithm for object searching. This algorithm is designed with principle that it first searches in cluster, and then searches between clusters. Through the simulation experiments, it has been confirmed that, comparing with the existing classic P2P overlay network, our algorithm has superiority in average network latency and average searching path's length.Finally, we have also used NSWO network's characteristics to propose a set of algorithm for congestion control, in order to handle the flash crowd caused by popular object's appearance in network. The simulation experiments have indicated that this algorithm has a good congestion control ability.