Differentiated search in hierarchical peer-to-peer networks

Although the original intent of the peer-to-peer (P2P) concept is to treat each participant equally, heterogeneity widely exists in deployed P2P networks. In this paper, we suggest to improve the search efficiency of P2P network by utilizing the query answering heterogeneity. Our proposed differentiated search (DiffSearch) algorithm can evolve an unstructured P2P network to a two-tier hierarchical structure, where peers with high query answering capabilities are grouped in the first tier, which has higher priority to be queried than the second tier. Because the query answering capability is extremely unbalanced among peers, a high query success ratio can be achieved by querying only a small portion of the network. The search traffic is dramatically reduced due to the shrunken search space. Our trace analysis and simulation show that the DiffSearch algorithm can save up to 60% of search traffic.