Routing and spectrum assignment with delayed allocation in elastic optical networks

In response to bandwidth-hungry applications, the field of elastic optical networks (EONs) has emerged. In this paper, we investigate the provisioning and allocation problem in EONs, which presents a number of new and exciting challenges not otherwise present in optical networking solutions.We propose a novel technique for solving the routing and spectrum allocation problem, which improves resource allocation efficiency for scheduled demands. This approach, called delayed spectrum allocation (DSA), promises network resources to each demand upon request for scheduling, but delays the selection and allocation of those specific resources until immediately before the transmission begins. Through extensive simulations, we are able to conclude that the DSA improves resource consumption efficiency and lowers call blocking. We also evaluate demands with flexible reservation windows such that a range of acceptable start times can be specified by the user. This flexibility is found to significantly increase the performance improvement of the DSA with little additional delay.