Design of path-segment-protecting p-cycles in survivable WDM mesh networks

Survivability is an essential feature in the design of WDM mesh networks for continuous service delivery in the case of failures. Segment p-cycles (also known as flow p-cycles) offer an interesting protection approach with a good trade-off between protection capacity cost and recovery speed. In this paper, we propose a new design method for segment p-cycles based on a large scale optimization tool, namely column generation techniques (CG). In contrast with the conventional design approaches which pre-enumerate the candidate segment p-cycles and establish their protection relationships with the protected capacity, our CG based optimization approach dynamically generates segment p-cycles with their protection capabilities during the optimization process. Computational results show that our design approach of segment p-cycles is much more capacity efficient and scalable than the prevalent design approach in the literature. A saving of protection capacity in the range of 3% to 20% is achieved. In addition, our CG-based design is highly scalable, and much faster in large dense networks than the prevalent classical ILP-based optimization approach.