Abstract-The possibility of using flexible and cost-efficient commodity hardware instead of expensive custom hardware has triggered wide interest in software routers. Performance measurement and simulation are important approaches for identifying bottlenecks of such systems to predict and improve the performance. We measure the performance of software routers using current multi-core hardware architectures. We introduce an innovative and validated node model for intra-node resource contention and realized a resource management extension for the widely-used network simulator ns-3 which allows to evaluate and predict the performance of current and future software router architectures.