Multistage Software Routers in a Virtual Environment

Open source routers (OSR), i.e. routers running on commodity personal computers (PC), represent a valid alternative to proprietary hardware routers. However, they may suffer from performance impairments and software limitations. Multistage architectures, based on the interconnection of elements running on standard PCs, improve single stage OSR performance. Virtualization technologies may permit to make a further step towards performance improvement (by aggregation of multiple elements into a single logical unit), increased flexibility (e.g. scalability, maintenance, consolidation) and easier introduction of new features (e.g. energy saving mechanisms). In this paper we study a previously proposed multistage architecture and consider its implementation when using virtual machines as internal components. In our experiments we demonstrate the feasibility of the architecture, and discuss some issues related to performance and architecture control.