Implementation of WFQ in a distributed open software router

There has been a considerable body of research devoted to the design and performance of PC based software routers running open source software. Most of the research on open software routers (OSRs) have focused on improving the performance of single PCs with a few proposals for a distributed design. Modern routers are equipped with enhanced functionality such as QoS features in addition to packet forwarding. However, providing enhanced functionality in distributed OSR architectures has largely remained unaddressed. A distributed design introduces challenges in its implementation due to looser coupling between different subsystems. WFQ is a widely used scheduler that enables QoS features in a router. The inherent centralized nature of the design of WFQ schedulers in most switches and routers creates several challenges when exported to distributed architectures. In this paper, we study the challenges of implementing WFQ in a distributed OSR, propose some novel techniques to address these challenges and compare the performance of our WFQ implementation in distributed OSR with that of a centralized WFQ scheme.