Delay constrained traffic grooming in WDM ring networks

In this paper we study the end-to-end delay constrained traffic grooming problem in WDM ring networks. Our aim is to incorporate Quality of Service (QoS) routing constraints into traffic grooming and address them jointly with the objective of maximizing the network throughput. It is well known that many real-time multimedia traffic not only make use of a fraction of the total wavelength capacity, but also have stringent end-to-end delay requirements. Consequently, while provisioning delay-bounded sub-wavelength traffic, it is of paramount importance to take traffic grooming and QoS routing constraints into consideration simultaneously to reduce the total network cost and improve the overall network performance. In this paper we first present an Integer Linear Program (ILP) formulation for the problem, which is applicable when the problem size is small. We then propose three scalable heuristic algorithms. We finally conduct experiments by simulation to evaluate the performance of the proposed algorithms. The experimental results show that, among the three proposed heuristics, the one based on ILP relaxation offers the best performance.