COMMUNICATIONS RESEARCH COLLOQUIUM AND INFORMAL SEMINAR Date: Wednesday, November 12, 2003. Time: 11:00am-12:00pm Place: 310 Rhodes Speaker: Rimon Barr Title: JiST: JAVA IN SIMULATION TIME FOR SCALABLE SIMULATION OF MOBILE AD HOC NETWORKS ABSTRACT Discrete event simulators are important scientific tools. For example, research in the areas of wireless ad hoc and sensor networks is fundamentally dependent on simulators. Yet, existing tools for modelling the behaviour of such networks are often unsatisfactory, because they severely limit the possible scale, level of detail or duration of the simulation results. In this talk, I will describe a new approach for constructing discrete event simulators that leverages virtual machines and combines the traditional systems-based and language-based approaches to simulator construction. JiST, for Java in Simulation Time, is a simulation engine that embodies this new technique. It embeds simulation execution semantics directly into the Java virtual machine. I will explain how the basic system works and then demonstrate that this approach is not only surprisingly efficent, but also flexible. Finally, I will illustrate a practical application of JiST through SWANS, a Scalable Wireless Ad hoc Network Simulator that runs atop JiST. SWANS can simulate wireless networks of 100,000 nodes and up, more than an order of magnitude larger than what existing simulators can achieve on equivalent hardware. Semester program: http://cn.ece.cornell.edu/links/comm-seminar/.