Topology awareness of overlay P2P networks

Abstract

In overlay networks, the mechanism of a peer randomly joining and leaving a network, causes a topology mismatch between the overlay and the underlying physical topology. This causes a large volume of redundant traffic in the underlying physical network as well as an extra delay in message delivery in the overlay network. Topology mismatch occurs because overlay networks are not aware of their underlying physical networks. In this paper we present a mathematical model for topology awareness of overlay networks (degree of matching between an overlay and its underlying physical network) and the efficiency of message delivery on them. Then we experimentally show that the model is precise in the real world. Also, after determining the computational complexity of the model, we propose an optimization heuristic algorithm to enhance efficiency of message exchange on overlay networks by increasing their topology awareness. Next, we present the results of running the algorithm on different kinds of random graph and show how we can implement the algorithm on peer-to-peer networks; we then simulate the implementation on some unstructured peer-to-peer overlay networks. Copyright © 2006 John Wiley & Sons, Ltd.