Multicast routing algorithms for sparse splitting optical networks

This work proposes novel routing approaches for transparent optical networks where only a fraction of the network nodes are multicast capable (MC) and can split the optical power from a single input to multiple output ports. The remaining, multicast-incapable (MI) nodes, can have either Drop-or-Continue (DoC) or Drop-and-Continue (DaC) capabilities. For the case of DaCs, if a MI node is a destination of the multicast group, it can drop a fraction of the incoming signal locally and transmit the rest to the next node. The current paper presents an Integer Linear Programming (ILP) formulation as well as novel heuristic multicast routing algorithms under the sparse-splitting constraint, for networks with or without DaC nodes. Performance results show that the proposed algorithms achieve an important decrease of the average cost of the derived solutions, compared to existing relevant techniques, and attain results very close to the lower bound provided by the ILP.