A lightpath allocation strategy for fair routing in WDM networks

We present a lightpath allocation strategy for fair routing in wavelength division multiplexing (WDM) optical networks without wavelength conversion. The strategy is able to yield more even pairwise blocking probabilities without much sacrificing average one. This is achieved through using alternate routing to gain network utilization and using an analytical model incorporating path-selection criteria to systematically allocate for each source-destination (SD) pair a set of alternate routes. In particular, the set is built with the smallest granular component lightpath in contrast to the conventional physical path consisting of a bundle of lightpaths. Additionally, the allocation exploits packing density gains by first exhausting lightpaths using a given wavelength to some extent before using another. Simulation results show that the analytical model is sufficiently accurate for identifying a target SD pair to be augmented with one more alternate lightpath, and that the proposed strategy compared with others is able to achieve significantly better uniformity of pairwise blocking probabilities even with different network parameters and topologies.