The disjoint path-pair matrix approach for online routing in reliable WDM networks

In reliable wavelength division multiplexed (WDM) networks, the optimal choice of routing and wavelength assignment (RWA) for the working and protection path-pair is often a complex problem to solve. To cope with such problem complexity, this paper presents the disjoint path-pair matrix (DPM) approach. With the DPM approach, the RWA problem complexity - i.e., the size of the solution space - can be significantly reduced by limiting the number of candidate path-pairs considered in the optimization. Simulation results are collected using the DPM approach to solve the online RWA problem in a network based on the shared path protection switching scheme with differentiated reliability. When compared to the conventional k-shortest paths approach, the DPM approach requires up to one order of magnitude less candidate path-pairs. In addition, the DPM approach finds solutions with reduced hop length of both the working and protection paths by up to 3% and 14%, respectively.