Dynamic scheduling of lightpaths in lambda grids

Dynamic optical networks hold the potential of satisfying very large bandwidth requirements of many of the grid applications. However, encapsulation of optical network elements into manageable grid resources and dynamic provisioning of lightpaths is necessary to meet the complex demand patterns of the grid applications and to optimize usage of optical network components. In this paper, we first present a scalable algorithm for an NP-hard problem of scheduling on-demand and advance reservation requests for lightpaths. We then investigate in detail the effect of proportion of advance reservations, laxity and distribution of the size of data transfer requests on performance through extensive experimentation. The paper also investigates that how much improvement in performance can be gained by segmenting large data transfer requests into multiple requests of smaller sizes and up to what percentage of overheads is segmentation justified in scheduling of lightpaths. We demonstrate how laxity can be exchanged for segmentation to achieve high utilization of lightpaths.