Center-Super-Leaf P2P: A Topology Matching P2P Network Model

At present, P2P (Peer-to-Peer) network is very hot in the field of not only academic research but also application research. In P2P network a node is both a client and a server that makes greater use of the network idle resources. Also because of its unique network structure and the search algorithm, P2P network makes the third-generation network computing model more advantages.In this paper,starting from the concept of P2P network, the characteristics, applications, classification and current hot points of P2P network were introduced in detail. On the basis of the vital problem to be solved of P2P network, a detailed analysis about current work on the topology mismatching problem was given. The problem of P2P network topology mismatching, which not only add to the burden of physical network nodes but increase the average time delay when searching resources, will cause unnecessary network traffic. The structured and unstructured P2P networks including their respective advantages and disadvantages were introduced. Especially, this paper focused on the analysis of Chord which is the representative of the structured P2P network's search technology. A detailed briefing on the Internet network structure and commonly used routing protocol BGP4 among autonomy systems was given. On this basis, the CSL (Center-Super-Leaf) P2P network model based on physical topology was proposed.There were three layers in CSL model. They were Center layer based upon the physical links among Autonomic Systems, super layer based upon the network addresses of peers, and leaf layer built by common nodes. Meanwhile corresponding algorithm to run the network was given. When designing the CSL model, the application layer and network layer could be considered together and a more applicable hash function was given.The experiments showed that in CSL model, the average time delay for information searching between peers could be obviously decreased. Especially when there were large-scale peers in P2P network, it could performance better in decreasing both the overhead of the physical network and the average time delay for information searching between peers. CSL model based on physical topology had a lower mismatching degree.