Reliable Hierarchical Peer-to-Peer File Sharing Systems

This paper presents an approach for hierarchical peer-to-peer (P2P) file-sharing systems in the design of the fault tolerance. In the hierarchical P2P system, peer nodes are organized into groups, and each group has a special peer node called superpeer to manage the regular peer nodes in the group. With this hierarchical characteristic, the proposed approach utilizes the superpeer node to tolerate the failures of the regular peer nodes. Unlike traditional P2P fault-tolerant approaches, the proposed fault-tolerant approach neither replicates the contents of the sharing files nor adds redundant overlay connections. Instead, it keeps track of the file retrievals in the superpeer node to support the fault tolerance. The cost of tracking the file retrievals is far smaller than the cost of replicating the file content. Furthermore, the proposed approach also considers the fault tolerance of the superpeer node by using the registration technique. The registration technique also takes a small cost in storing the file location information. Finally, the overall fault-tolerant cost of the proposed approach is analyzed to compare with other related approaches