Workload Generation for ns Simulations of Wide Area Networks and the Internet

摘要

Extreme complexity of wide area networks and the Internet make the development of analytic models very difficult and under such circumstances, simulation models are a viable alternative to understand the behavior of these networks. We use ns (ns 1997) as the simulation platform for this paper largely because of its wide acceptance in the networking community and its open design suitable for modification. A major drawback of ns is its failure to generate workloads and traffic patterns for networks which require taking into account the temporal and spatial correlation between the sources and the traffic that they generate. Also, a realistic traffic generator must maintain the proper composition of the composite traffic which results from the contributions of various protocols and applications in the network. In this paper we propose methodologies to address these issues and describe their implementation in ns. In addition, to address the issue of generating long-range dependent traffic in ns, we have implemented two self-similar traffic sources based on Fractional Renewal Processes and Markov Modulated Poission Process. We also validate the proposed techniques and traffic generators using extensive simulations and present the simulation results.