A taboo-based search algorithm to enhance multicast routing under multiple additive constraints

The fulfilment of guaranteed multiple criteria based quality of service (QoS) for multimedia applications servicing multiple subscribers is known to be a NP complete problem. Moreover, finding the multicast graph respecting the defined QoS requirements and minimizing network resources is also a NP-complete optimization task. The well-known greedy algorithm Mamcra, proposed in the literature, computes the set of shortest paths from a source to all destination, and then reduces this set to an efficient set of multicast routes, without compromising the requested level of QoS. A closer look at Mamcra shows that it does not exploit further simple but possible reductions of the multicast sub-graph. In this paper, we propose a taboo search algorithm, named TabooQMR, that is augmented by some meta-heuristics to improve the multicast sub-graph computed by the greedy algorithm Mamcra, and leading to a considerable improvement, as demonstrated by the simulation results.