This paper presents a new practical approximation algorithm for wavelength assignment to splitable lightpaths over WDM rings, with the objective of minimizing the number of SONET ADMs. Allowing the splitting of traffic streams can significantly reduce the number of required ADMs.
Moreover, while finding the best assignment is proved to be NP-Hard, the problem seems easier to approximate than the variation when traffic streams cannot be split. In the worst case, the output of the new polynomial-time algorithm is at most 25% more than the optimum solution. This result is significantly better than the best known approximation ratio for non-splitable traffic streams.