Research On Resource Locating Technologies In Unstructured Peer-to-Peer System

The past several years witness the rapid development of P2P systems. Efficient resource locating scheme becomes the key technology of P2P systems. Traditional resource locating scheme is based on flooding algorithm, which occupies too much bandwidth on network constructing and resource locating. The overhead of locating is very large and bandwidth barrier of low-bandwidth peers is caused. What's more, free-riding phenomenon results in long delay and low performance of resource locating. All these problems prohibit the rapid development of P2P system. How to decrease the bandwidth used by resource locating scheme and how to reduce the latency of resource locating become an important subject of the P2P system research field.The P2P system resource locating scheme has three components: overlay network constructing, locating information processing and assistant locating requirement processing. The constructing of overlay network focuses on how to resolve bandwidth barrier of low-bandwidth peers. Super-peer overlay network is an efficient solution. However, current super-peer overlay network behaves badly in terms of robustness and efficiency of constructing protocol. How to construct an efficient and robust super-peer overlay network is challenging. Locating information processing aims at improving locating performance and reducing overhead, which includes BFS-like and DFS-like methods. DFS-like methods which cost less overhead adapt themselves to large- scale P2P systems, but they bring long locating latency. How to improve locating performance and keep low overhead still needs further study. Assistant locating requiring processing mainly utilizes resource replicas to reduce locating latency. However, how to balance the performance and replication overhead and how to keep consistency of resource replica in the dynamic P2P systems are still demanding. Detailed research works have been done on the above issues. The main contributions are as follows:1. ERSN, an efficient and robust super-peer overlay network is presented. Overlay network constructing protocol and topology structure of traditional super-peer overlay network are analyzed. ERSN estimates the requirement of actual network by peer sampling protocol, and constructs super-peer overlay network. Thus the constructing efficiency of overlay network is improved. ERSN establishes the emergence links between the leaf-peers, which are available for leaf-peers losing super-peers to require for resource. Thus the robustness of super-peer overlay network is improved.2. ARW, an efficient locating requiring processing algorithm is presented. In order to improve locating performance without enlarge overhead, ARW utilizes path information carrying and walker self-replicating technologies. The number of peers accessed by walk-...