Multi-domain traffic partition grooming in mixed granularity optical networks

In wavelength-division-multiplexing (WDM) optical networks, the demands characterized by coarse and fine granularity cause the poor resource utilization of lightpaths in traffic grooming and an excessive utilization of (de)-multiplexing ports in waveband switching. More specifically, once a lightpath carries a coarse-granularity demand with a near-wavelength capacity, it will not be able to hold other demands; once a waveband carries a large amount of fine-granularity demands each with a very small wavelength fraction, the number of (de)-multiplexing ports will increase sharply. We call these inefficient situations as gra-diversity problems. Furthermore, with the large scale of the backbone, the optical network has been divided into multiple domains for achieving the scalability in the real world. Thus in this paper, we study gra-diversity problems and facilitate the novel traffic partition grooming with the granularity-layered graph (GLG) in the mixed granularity and multi-domain optical networks. Our heuristic is composed of three basic components: (a) the traffic grooming of fine-grained demands, (b) the waveband switching of coarse-grained demands, and (c) the demand migration that is achieved through the interconnection of different granular layers in GLG. Extensive simulation results demonstrate the effectiveness of our method on improving the resource utilization and mitigating port consumptions by well solving gra-diversity problems in the mixed granularity and multi-domain optical networks. From the comparisons between our method and benchmarks, we find that the average improvement ratio of blocking rate arrives at 34%, and the average ratio of port savings is about 3%.