Optimal standby virtual routers selection for node failures in a virtual network environment

Network virtualization allows flexibility to configure virtual networks in a dynamic manner. In such a setting, to provide resilient services to virtual networks, we consider the situation where the substrate network provider wants to have standby virtual routers ready to serve the virtual networks in the event of a failure. Such a failure can affect one or more virtual routers in multiple virtual networks. The goal of our work is to make the optimal selection of standby virtual routers so that virtual networks can be dynamically reconfigured back to their original topologies after a failure. We present an optimization formulation and a heuristic for this problem. By considering a number of factors, we present numerical studies to show how the optimal selection is affected. The results show that the proposed heuristic's performance was close to the optimization model when there were sufficient standby virtual routers for each virtual network and the substrate nodes have the capability to support multiple standby virtual routers to be in service, concurrently.