Dynamic manycasting in optical split-incapable WDM networks for supporting high-bandwidth applications

With the advent of bandwidth intensive applications, the demand for manycast networking capabilities has become an essential component of wavelength division multiplexed (WDM) optical networks. Traditionally, the manycast functionality is accomplished by splitting a signal all-optically, thereby creating a light-tree, which originates from the source node and reaches a subset of the destination nodes. To support the manycasting functionality in an optical network that is split-incapable (SI), i.e., the optical crossconnects are incapable of switching an incoming optical signal to more than one output interface, one must implement a logical overlay to the underlying optical layer. A naiıve approach to accomplish this is by creating a set of unicast lightpaths that originate at the source node and terminate at a subset of the destination nodes of the manycast request. We refer to this as the manycasting via WDM unicast (MA-VWU) approach. However, for a large number of requests this approach leads to a poor utilization of network resources. To overcome this problem, we propose two overlay approaches: manycasting with drop at member node (MA-DAMN) and manycasting with drop at any node (MA-DAAN). In these solutions, we achieve manycasting by creating a set of lightpath routes (possibly multiple hops) in the overlay layer. We consider a dynamic traffic model and propose efficient heuristics to solve the MA-DAMN and MA-DAAN problems with a goal of minimizing the total number of wavelengths required to satisfy the requests. Our results demonstrate that both the overlay approaches reduce the wavelength consumption by approximately 33-45% over the MA-VWU approach for real-world large-scale networks¹.