Low latency packet processing in software routers

Commodity hardware can be used to build a software router that is capable of high-speed packet processing while being programmable and extensible. Therefore, software routers provide a cost-efficient alternative to expensive, special hardware routers. The efficiency of packet processing in resource-constrained nodes (e.g. software routers) can be strongly increased through parallel processing with commodity hardware based on multi-core processors. However, intra-node resource contention can have a strong negative impact on the corresponding network node. We describe how multi-core software routers can be optimized for low latency support by utilizing the technologies available in commodity PC hardware. For the analysis we used our approach for modeling of resource contention in resource-constrained nodes which is also implemented as the resource-management extension module for ns-3. Based on that, we derived a specific software router model which we used to optimize the performance. Our measurements show that the configuration of a software router has significant influence on the performance. The results can be used for parameter tuning in such systems.