Impairment-aware optical multicast tree design with modulation format optimization

A novel optical multicast tree design algorithm is proposed for elastic optical path networks; it considers signal regeneration and modulation format adaptation. The algorithm minimizes not only the number of costly regenerators needed, but also the total frequency slots necessary by optimizing the modulation formats applied. By formulating the problem as two-stage integer linear programming on an auxiliary graph, the proposed algorithm successfully calculates optimal trees on large networks within several tens of seconds.