Leveraging Light Forest With Rateless Network Coding to Design Efficient All-Optical Multicast Schemes for Elastic Optical Networks

In this paper, we study the multicast-capable routing, modulation, and spectrum assignment (MC-RMSA) schemes that consider the physical impairments from both the transmission and light splitting in elastic optical networks (EONs). Specifically, we propose to provision each multicast request with a light forest, which consists of one or more light trees to avoid the dilemma that because of the accumulated physical impairments, a relatively large light tree may have to use the lowest modulation level, and, hence, consume too many frequency slots (FS'). In order to further improve the spectral efficiency and compensate for the differential delays among the light trees, we incorporate the rateless network coding (R-NC) in the multicast system. We first formulate an integer linear programming (ILP) model to solve the problem for static network planning. Then, we propose three time-efficient heuristics that leverage the set-cover problem and utilize layered auxiliary graphs. The simulation results indicate that in both the ILP and heuristics, the MC-RMSA with R-NC can achieve better performance on the maximum index of used FS' than that without. After that we evaluate the heuristics in a dynamic network provisioning. The results show that the MC-RMSA with R-NC can effectively improve the performance of all-optical multicast in EONs to reduce the blocking probability.