An Optimal Overlay Topology for Routing Peer-to-Peer Searches

Unstructured peer-to-peer networks are frequently used as the overlay in various middleware toolkits for emerging applications, from content discovery to query result caching to distributed collaboration. Often it is assumed that unstructured networks will form a power-law topology; however, a power-law structure is not the best topology for an unstructured network. In this paper, we introduce the square-root topology, and show that this topology significantly improves routing performance compared to power-law networks. In the square-root topology, the degree of a peer is proportional to the square root of the popularity of the content at the peer. Our analysis shows that this topology is optimal for random walk searches. We also present simulation results to demonstrate that the square-root topology is better, by up to a factor of two, than a power-law topology for other types of search techniques besides random walks. We then describe a decentralized algorithm for forming a square-r...

• Type: Conference
• Year: 2005
• Where: MIDDLEWARE
• Authors: Brian F. Cooper
• Keywords: MIDDLEWARE 2005, Power-law Topology, Square-root Topology, Unstructured Network