Understanding Individual Nodes in Peer-to-Peer Systems

This paper addresses a simple question: Is there a behavior pattern of an individual node in peer-to-peer systems? It is known that peer-to-peer systems collectively show daily patterns, but the behavior patterns of individual nodes have seldom been studied. If individual nodes have their own behavior patterns with reasonable accuracy, we could greatly improve the efficiency of the system by reducing the overhead to handle unexpected random node failures. Even though there have been many empirical studies on peerto-peer systems, most of them are focusing on a collective view to characterize the whole systems in terms of average availability, average session length, and so on. In this paper we present Peer Availability Table (PAT) which is a model to represent a behavior pattern of an individual node based on the measurement of node availability. To judge the existence of the behavior pattern, we measure the performance of PAT using a binary classification test. By answering the basic question, we provide a useful hint for the design of peer-to-peer systems.