Dynamic advance reservation multicast overlay for slotted optical WDM networks

In this paper we investigate techniques for provisioning advanced reservation multicast requests in Multicast-Incapable (MI) networks, which lack the ability to split an incoming signal to multiple output ports, without performing an O-E-O conversion. To implement the multicasting functionality in a MI network, we propose implementing it as a logical overlay to the optical layer. One such method is to reserve unicast lightpaths from the source node to each destination node of the multicast request. Referred to as Multicast Via WDM Unicast (MVWU), this solution tends to utilize the network resources in an inefficient manner. To address this problem we propose two novel overlay solutions: Drop At Member Node (DAMN) and Drop At Any Node (DAAN), wherein we create a set of lightpath routes (possibly multiple-hop) in the overlay layer to reach all the destinations of a multicast request. In DAMN, we allow a lightpath to terminate/originate only at nodes which belong to the set of destination nodes of the multicast request. DAAN relaxes this constraint and allows a lightpath to be terminated at any node in the network. We refer to the set of lightpath routes created in the overlay layer as overlay-trees. We consider dynamic traffic and present efficient heuristics to solve the MVWU, DAMN, and DAAN problems with a goal of minimizing the blocking probability of a request. Our results indicate that DAMN and DAAN outperform the MVWU approach. Further, we present different mechanisms to generate the overlay-trees and compare their relative performance on a real-world large-scale network.