Research And Development Of File Sharing System Based On Hybrid Hierarchical P2P Network

Along with the technical development of peer-to-peer (P2P), the distributed file sharing systems built on it are rapidly becoming one of the most popular applications on the Internet. The typical topologies of P2P networks that a file sharing application can be established on are three types: central server P2P, unstructured P2P and structured P2P. File sharing system based on central server P2P can be implemented easily, but it has several problems which are as same as the system based C/S structure because of the central server. At present, the most existing file sharing systems are based on unstructured P2P network using flooding method for search. Although these systems are stable for the dynamic networks, they are inefficiency and usually generate much burden on the network because of their flooding mechanism. New researches mainly focus on structured P2P network using distributed hash table (DHT) to enhance the system performance. Structured P2P networks are efficiency and scalable. However, the applications based on DHT are not popular since DHT maintenance mechanism is complicated and the network churn caused by the frequent joining or leaving of peers can enormously increase DHT maintenance costs. In this thesis, we proposed a file sharing system (Kapa) based on a hybrid hierarchical P2P network (HP2P) which is a two-layer hybrid P2P network that uses Chord as the upper layer and Cluster as the lower layer. File sharing systems based on HP2P benefit from the advantages of both structured and unstructured networks and have high efficiency, good scalability and fine stability. In this thesis, the structure of HP2P, the data structure, node joining, node leaving, routing table stabilizing and lookup services are introduced. Further the implementation of file sharing module is described in detail. Finally, the simulation results are shown to validate the features of Kapa system.