Efficient content search in iShare, a P2P based Internet-sharing system

This paper presents an efficient content search system, which is applied to iShare, a distributed peer-to-peer(P2P) Internet-sharing system. iShare facilitates the sharing of diverse resources located in different administrative domains over the Internet. For efficient resource management, iShare organizes resources into a hierarchical name space, which is distributed over the underlying structured P2P network. However, iShare's search capability has a fundamental limit inherited from the underlying structured P2P system's search capability. Most existing structured P2P systems do not support content searches. There exists some research that provides content search functionality, but the approaches do not scale well and incur substantial overheads on data updates. To address these issues, we propose an efficient hierarchical-summary system, which enables an efficient content search and semantic ranking capability over traditional structured P2P systems. Our system uses a hierarchical name space to implement a summary hierarchy on top of existing structured P2P overlay networks, and uses a Bloom Filter as a summary structure to reduce space and maintenance overhead. We implemented the proposed system in iShare, and the results show that our search system finds all relevant results regardless of summary scale and the search latency increases very slowly as the network grows.