Performance Evaluation of Dynamic Networks using an Evolving Graph Combinatorial Model

The highly dynamic behavior of wireless networks make them very difficult to evaluate, e.g. as far as the performance of routing algorithms is concerned. However, some of these networks, such as intermittent wireless sensors networks, periodic or cyclic networks, and low Earth orbit (LEO) satellites systems have more predictable dynamics, as the temporal variations in the network topology are somehow deterministic. Recently, a graph theoretic model-the evolving graphs-was proposed to help capture the dynamic behavior of these networks, in view of the construction of least cost routing and other algorithms. The algorithms and insights obtained through this model are theoretically very efficient and intriguing. However, there is no study on the uses of these theoretical results into practical situations. Therefore, the objective of this work is to analyze the applicability of the evolving graph theory in the construction of efficient routing protocols in realistic scenarios. In this paper, we used the NS2 network simulator to first implement an evolving graph based routing protocol, and then to evaluate such protocol compared to three major ad-hoc protocols (DSDV, DSR, AODV). Interestingly, our experiments showed that evolving graphs have all the potentials to be an effective and powerful tool in the development of algorithms for dynamic networks, with predictable dynamics at least. In order to make this model widely applicable, however, some practical issues still have to be addressed and incorporated into the model, like stochastically predictable behavior. We also discuss such issues in this paper, as a result of our experience