PC-based Router Virtualization with Hardware Support

In this paper we focus on how to use open source Linux software in combination with PC hardware to build high speed virtual routers. Router virtualization means that multiple virtual router instances will run in parallel on the same hardware. To enable this, virtual components are combined in the router's data plane. This can result in performance penalties. Furthermore, an overloaded virtual router can affect the performance of other virtual routers running in parallel. Achieving high performance and strong performance isolation in a virtualized environment is challenging. We investigate how hardware can help to achieve these goals in the Linux Namespaces environment. We propose a forwarding architecture for virtual routers based on multi-core hardware where virtual routers can run in parallel on different CPU cores. This reduces resource contention among virtual routers and results in improved performance and isolation. To enable this architecture, we find that hardware based I/O virtualization support is essential. We demonstrate this by making a comparison with a software based I/O virtualization approach. We also show that hardware assisted virtual routers can achieve better aggregate throughput than a non-virtualized router on a multi-core platform.