Minimizing the number of multicast transmissions in single-hop WDM networks

The problem of minimizing the number of transmissions for a multicast transmission under the condition that the packet delay is minimum in single-hop WDM networks is studied in this paper. This problem is proved to be NP-complete. A heuristic multicast scheduling algorithm is proposed for this problem. The performance of the proposed scheduling algorithm is compared with two other multicast scheduling algorithms by extensive simulations. Our simulation results show that (i) the proposed heuristic algorithm always produces lower mean packet delay than the other two algorithms, and (ii) an algorithm which partitions a multicast transmission into multiple unicast or multicast transmissions may not always produce lower mean packet delay than the algorithm which does not partition a multicast transmission into multiple transmissions when the number of data channels in the system is limited