Scheduled multicast overlay for bandwidth-intensive applications

In this paper we investigate the multicast advance reservation problem in wavelength division multiplexed (WDM) optical networks. Under the advance reservation traffic model (also know as scheduled traffic), connection requests specify their start time to be some time in the future and also specify their holding times. Traditionally, in WDM networks, the multicasting functionality is supported by assuming that the optical cross connects are multicast capable i.e., they are capable of switching an incoming signal to multiple output interfaces. To support the multicasting functionality in a multicast incapable (MI) network, one can use a naive approach of creating a virtual topology consisting of wavelength routes (lighpaths) from the multicast source to each destination of the multicast session. This approach tends to consume a lot of network bandwidth and may become unacceptable as the number of the multicast sessions increase. We refer to this approach of provisioning the multicast requests as Multicast via WDM Unicast (MVWU) approach. To efficiently provision the users´ scheduled multicast requests in a MI network, we propose two overlay solutions: Drop at Member Node (DAMN) and Drop at Any Node (DAAN). In these solutions, we achieve multicasting by creating a set of lightpath routes (possibly multiple hops) in the overlay layer. We consider a static set of scheduled multicast requests and present integer linear programs (ILPs) to solve the DAMN and DAAN problems, with a goal to minimize the total number of wavelengths required to service the request set. We also present an efficient heuristic and compare its performance to the ILP for a small network, and evaluate its performance for large-scale networks. Moreover, we also present an ILP to solve the naive MVWU approach and compare its performance to the DAMN and DAAN.