Divide et Impera: Partitioning Unstructured Peer-to-Peer Systems to Improve Resource Location

Abstract

Unstructured P2P systems exhibit a great deal of robustness and self-healing at the cost of reduced scalability. Resource location is performed using a broadcast-like process called flooding. The work presented in this paper comprises an effort to reduce the overwhelming volume of traffic generated by flooding, thus increasing the scalability of unstructured P2P systems. Using a simple hash-based content categorization method the Ultrapeer overlay network is partitioned into a relatively small number of distinct subnetworks. By employing a novel index splitting technique each leaf peer is effectively connected to each different subnetwork. The search space of each individual flooding is restricted to a single partition, and is thus considerably limited. This reduces significantly the volume of traffic produced by flooding without affecting at all the accuracy of the search method. Experimental results demonstrate the efficiency of the proposed method.