An experimental study of stability in heterogeneous networks

Abstract

A distinguishing feature of today's large-scale communication networks, such as the Internet, is their heterogeneity, predominantly manifested by the fact that a wide variety of communication protocols are simultaneously running over different network hosts. A fundamental question that naturally poses itself for such common settings of heterogeneous networks concerns their ability to preserve the number of packets in the system upper bounded at all times. This property is well-known as stability. We focus on the Adversarial Queueing Theory framework, where an adversary controls the rates of packet injections and determines packet paths. In this work, we present specific network constructions with different protocol compositions and we show experimentally their stability behavior under an adversarilly strategy. In particular, we study compositions of universally stable protocols with unstable protocols like FIFO. Interestingly, some of our results indicate that such a composition leads to a worst stability behavior than having a single unstable protocol for contention-resolution. This suggests that the potential for instability incurred by the composition of one universally stable protocol with one unstable protocol may be worse than that of some single protocol. © Springer-Verlag Berlin Heidelberg 2007.