An Integer Linear Programming Based scheme for Segment Based Path Protection in Elastic Optical Networks

This paper considers shared backup path protection in comparison with shared segment protection for elastic optical networks. The problem is formulated in an integer linear programming framework. The objective is to minimize the weighted function of the total used spare capacity and the maximal index of frequency slots used in the network. For the proposed shared segment protection scheme we assume that the network nodes are empowered with the frequency spectrum switching capability. Using this capability, we are able to decompose the working path into smaller segments and protect that segments against possible failures. Each segment of a connection behave as a self-healing and independent unit. If one link of working path is subject to any unexpected interruption, the restoration is performed only within the corresponding protection for that segment. In the case that the nodes are not empowered with the frequency spectrum switching capability, we use shared path protection. Since the physical distance of each segment and the possibility of simultaneous failure of segments for a given path is rare, the required spare capacity in the segment based scheme is decreased compared to the path protection. Simulation results show that the total spare capacity used in the shared path protection is 14/5% greater than the proposed shared segment protection scheme. Also, shared segment protection is more resilient against the simultaneous links failure events compared to the path protection.