Malleable Reservation Based Bulk-Data Transfer to Recycle Spectrum Fragments in Elastic Optical Networks

In this paper, we propose to facilitate efficient bulk-data transfer in elastic optical networks (EONs) with malleable reservation (MR). The MR scheme performs adjustable routing and spectrum assignment (RSA) for the data-oriented requests that each has certain amount of data to transfer in an EON, where there also exist flow-oriented requests that each requires a fixed bandwidth. We enable RSA reconfigurations for each data-oriented request served by MR, to effectively recycle the 2-D spectrum fragments (i.e, fragments existing in the time and spectrum domains with a correlated manner) generated by the flow-oriented requests. We first formulate a mixed integer linear programming (MILP) model for the MR problem to maximize the percentage of transmitted data using a limited number of RSA reconfigurations. Then, in order to reduce the time complexity, we propose a dynamic programming method (DPM) that can provide the exact solution to the MR problem in polynomial time. Simulation results suggest that compared with the MILP, DPM can provide exact MR solutions for the data-oriented requests with significantly reduced time complexity. The results also verify that without affecting the provisioning of flow-oriented requests, DPM can recycle 2-D spectrum fragments and improve the EON´s spectrum utilization effectively.