Valid inequalities for the routing and spectrum allocation problem in elastic optical networks

We deal with a natural integer-linear programming formulation of the routing and spectrum allocation (RSA) problem in elastic optical networks. We focus on strengthening the formulation with valid inequalities (cuts). For this purpose we apply clique inequalities that proved to be useful in other applications of this kind. We develop and combine a clique cut generation procedure with a column generation algorithm with the aim to improve the quality of generated columns. The presented results, obtained for a set of problem instances, illustrate the effectiveness of the optimization algorithm.