Distributed Packet-Level Simulation for BGP Networks under Genesis

The complexity and dynamics of the Internet is driving the demand for scalable and efficient network simulation. Parallel and distributed network simulation techniques make it possible to utilize the power of multiple processors or clusters of workstations to simulate large-scale networks efficiently. However, synchronization overheads inherent in parallel and distributed simulations limit the efficiency and scalability of these simulations. We developed a novel distributed network simulation framework and synchronization approach which achieved better efficiency than conventional approaches. In this framework, BGP networks are partitioned into domains of Autonomous Systems (ASes), and simulation time is divided into intervals. Each domain is simulated independently of and concurrently with the others over the same time interval. At the end of each interval, packet delays and drop rates for each interdomain flow are exchanged between domain simulators. The simulators iterate over the same time interval until the exchanged information converges to the value within a prescribed precision before progress to the next time interval. This approach allows the parallelization with infrequent synchronization, and achieves significant simulation speedups. In this paper, we focus on the design of distributed BGP network simulation in Genesis in which many BGP ASes can be assigned to a single Genesis domain. We also report our experimental results that measure Genesis distributed efficiency in large scale BGP network simulations.