MILP formulation for squeezed protection in Spectrum-Sliced Elastic Optical Path Networks

In Spectrum-Sliced Elastic Optical Path Networks (SLICE), the lightpath bandwidth is variable and can provide a finer granularity when compared to that of current optical path networks. Therefore, the virtual topology overlay on a physical topology must be designed considering new constraints and requirements to optimize the spectrum utilization, which has been recently investigated as a solution to a Mixed Integer Linear Program (MILP). In this paper we propose a mechanism that can provide both traffic survivability and efficient spectral utilization in SLICE networks by employing the spectrum flexibility and the novel concept of bandwidth sqeezing. A MILP formulation is presented that uses these new concepts to efficiently route the traffic in the network, while satisfying a committed bit-rate in the event of a failure. Cases studies are carried out in order to analyze the benefits of the proposal as well as the basic proprieties of the formulation.