Design, Performance and Dependability of a Peer-to-Peer network supporting QoS for mobile code applications

With the advent of web applications such as Napster, Gnutella and Freenet, peer-to-peer (P2P) networks have gained unprecedented importance in the networking world. In this paper we study the effect of different network parameters on the performance of P2P networks supporting mobile code applications, and analyze various quality of service (QoS) issues such as response times, jitter and loss probability. We derive analytic expressions for (a) the number of hops using graph-theoretic techniques and, (b) the QoS measures using probabilistic models. For our studies, we have used three types of network models, namely Erdös-Rényi graph, small world graph, and scale free graph. Further, we formulate and solve an optimization problem to design the number of indexes and time out value, where an index refers to a database that maps mobile codes to nodes that contain them.