Genesis: A scalable distributed system for large-scale parallel network simulation

The complexity and dynamics of the Internet is driving the demand for scalable and efficient network simulation. In this paper, we describe a novel approach to scalability and efficiency of parallel network simulations. This approach is based on partitioning of a network into domains and of the simulation time into intervals. Each domain is simulated independently of and concurrently with the others over the same simulation time interval. At the end of each interval, traffic statistics data, including per flow average packet delays and packet drop rates, are exchanged between domain simulators. The simulators iterate over the same time interval until the exchanged information converges, that is until the certain metric of a difference between the information exchanged in two subsequent iterations is smaller than a prescribed precision. After convergence, all simulators progress to the next time interval. This approach allows the parallelization with infrequent synchronization, and achieves significant simulation speedups.Large memory size required by simulation software hinders the simulation of large-scale networks. To overcome this problem, our system supports distribution of network information by assigning to each participating simulator only data related to the part of the network that it simulates. Such a solution supports simulations of large-scale networks on machines with modest memory size.