Stable Logical Topologies for Survivable Traffic Grooming of Scheduled Demands

There has been considerable research interest in the area of traffic grooming for WDM mesh networks. The vast majority of the current work can be classified into one of two categories, either static grooming or dynamic grooming. In many situations, the individual traffic demands require bandwidth at certain predefined intervals, and resources allocated to nonoverlapping demands can be reused in time. In this paper, we propose a new traffic grooming technique that exploits knowledge of the connection holding times of traffic demands to lead to more efficient resource utilization. We consider wavelength-convertible networks as well as networks without any wavelength conversion capability and implement survivability using dedicated and shared path protection. Although individual demands may be short lived, it is desirable to have a logical topology that is relatively stable and not subject to frequent changes. Therefore, our objective is to design a stable logical topology that can accommodate a collection of low-speed traffic demands with specified setup and teardown times. Our approach results in lower equipment cost and significantly reduced overhead for connection setup/teardown. We present efficient integer linear program (ILP) formulations that address the complete traffic grooming problem, including logical topology design, routing and wavelength assignment, and routing of traffic demands over the selected topology. The primary focus of our ILP formulations is to minimize the resource requirements. However, it is possible to modify our formulations to maximize the throughput, if necessary.