On the benefits of multi-path recovery in flexgrid optical networks

We propose a new recovery scheme, called multi-path recovery (MPR), specifically designed for flexgrid-based optical networks. It combines protection and restoration schemes to jointly recover, in part or totally, the bitrate requested by client demands in case of failure. We define the bitrate squeezed recovery optimization (BRASERO) problem to maximize the amount of bitrate which is recovered in case of failure of any single fiber link; a mixed integer linear programming formulation for the BRASERO problem is provided. However, since their exact solutions become impractical when real-sized network and traffic instances are considered, we develop a heuristic algorithm which provides a much better trade-off between optimality and complexity. Exhaustive numerical experiments carried out over realistic network topologies and traffic scenarios show that the efficiency of the proposed MPR scheme approaches that of restoration while providing recovery times as short as protection schemes.