Routing and Spectrum Assignment for Dual Failure Path Protected Elastic Optical Networks

We present the design of a dual failure protected elastic optical network (EON) for different sharing capabilities of protection lightpaths. Routing and spectrum assignment (RSA) is considered for such a network so as to minimize the maximum number of frequency slots (FSs) used. The key principles for protection resource sharing among the first and the second protection lightpaths are identified for dedicated 1:1:1, mixed 1:1:1, 1+1:1, and 1+1+1 protection. Both integer linear programming (ILP) models and spectrum window plane (SWP)-based heuristic algorithms are proposed for RSA in dual failure protected EONs. Simulation results indicate that, apart from being efficient, the proposed SWP-based heuristic algorithm not only performs close to the ILP model but also does much better than a benchmark adaptive routing algorithm. We find that 1:1:1 protection technique performs better in terms of the maximum number of FSs used and the spare capacity redundancy than both the 1+1:1 and 1+1+1 techniques. In addition, the mixed 1:1:1 case outperforms the dedicated 1:1:1 case both in minimizing the maximum number of link FSs used and its spare capacity redundancy.