Using decomposition techniques for the design of survivable logical topologies

We study the design of logical survivable topologies for service protection against single or multiple failures in IP-over-WDM networks where protection can be provided either at the optical layer, or at the network (IP) layer. Indeed, synergies need to be developed between IP and optical layers in order to optimize the resource utilization and to reduce the costs and the energy consumption of the future networks. We propose a new optimization model, an enhanced cutset model, which relies on a column generation reformulation for the design of a survivable logical topology. It is a highly scalable model and it makes possible the (near) exact solution of several benchmark instances, which were only solved with the help of heuristics so far. In addition, much larger instances than in previous studies can be solved as the proposed formulation avoids the explicit or implicit enumeration of cutsets. In the numerical experiments, we explore how survivability evolves when the number of failure sets increases.