A fast path-based ILP formulation for offline RWA in mesh optical networks

RWA is a fundamental problem in the design and control of optical networks. We introduce the concept of symmetric RWA solutions and present a new ILP formulation to construct optimally such solutions. The formulation scales to mesh topologies representative of backbone and regional networks. Numerical results demonstrate that the new formulation achieves a decrease of up to two orders of magnitude in running time compared to existing formulations. In particular, optimal solutions for topologies up to 20 nodes can be obtained within minutes using commodity CPUs, and larger networks can be solved in reasonable time. Our approach significantly lowers the barrier to entry in fully exploring the solution space of optical network design and in investigating the sensitivity of design decisions to forecast demands via extensive “what-if” analysis. Such analysis cannot be carried out currently without large investments in computational resources and time.