FBustamante-WCW03

Abstract

We consider the problem of choosing who to “be- friend” among a collection of known peers in dis- tributedP2Psystems. Inparticular,ourworkexplores anumberofP2Pprotocolsthat,byconsideringpeers’ lifespan distribution a key attribute, can yield systems with performance characteristics more resilient to the naturalinstability of their environments. This article presents results from our initial efforts, focusingoncurrentlydeployeddecentralizedP2Psys- tems. We measure the observed lifespan of more than 500,000peersinapopularP2Psystemforoveraweek andproposeafunctionalformthatfitsthedistribution well. We consider a number of P2P protocols based on this distribution, and use a trace-driven simula- tor to compare them against alternative protocols for decentralized and unstructured or loosely-structured P2P systems. We find that simple lifespan-based pro- tocols can reduce the ratio of connection breakdowns andtheir associated costs by over42%. Keywords: Peer-to-Peer, Lifespan, Pareto Distri- bution,Protocols, Empirical Study.