On the trade-off between cost and availability of virtual networks

To minimize cost, Virtual Network Operators (VNOs) need to consider the required network availability already at the network design stage. One generic approach to reach the availability target is to select only high-quality physical network elements that offer high availability and consequently demand high expenses per element. The other generic approach to achieve high availability is to add protection capacity on the level of the virtual network based on lower cost components. In this paper, we analyze both alternatives with a simulation tool to answer the fundamental question how quality can be traded against capacity. For this purpose, we consider different network topologies and the influence of different parameters and provide a framework to find an optimal strategy between Mean Time Between Failures (MTBF) targets for the physical infrastructure and the usage of additional backup paths on the virtual network level.