Many-to-one traffic grooming with aggregation in WDM networks

Most of the network applications bandwidth requirements are far less than the bandwidth offered by a full wavelength in WDM networks. Hence, traffic grooming is needed to make efficient use of the available resources. In this paper we address the grooming of many-to-one traffic demands in WDM networks on arbitrary topologies. Traffic streams from different sources, but part of the same session and thus terminating at the same destination, can be aggregated using arbitrary, but application dependent, aggregation ratios. We provide optimal as well as heuristic solutions to the problem. The objective is to minimize the cost of the network, by minimizing the total number of the higher layer components and the total number of the wavelengths used in the network. One of the main contributions of this work is to provide a mixed integer linear solution, to an otherwise non-linear problem, by exploiting the specifics of routing and aggregation sub-problems, while still maintaining the optimality of the solution. The formulation is generic and can handle varying amounts of traffic from each source to a common destination, as well as arbitrary aggregation fractions of the data coming from the different sources. This fraction is made to be a function of the number of the streams participating in the aggregation. For the heuristic solution we developed a Dynamic Programming style approach that builds the solution progressively, going through a number of stages, while choosing the best partial solutions among a number of possible partial solutions at each stage