Efficient spectrum assignment in Elastic Optical Networks

The Elastic Optical Network (EON) architecture has been proposed in response to the large capacity and diverse traffic granularity needs of the future Internet. By breaking the fixed-grid spectrum allocation of WDM networks, EONs increase the flexibility in terms of connection provisioning. The appropriate-sized optical spectrum is allocated to each connection depending on its requested bandwidth. The main weakness of EON, under dynamic traffic conditions, stems from spectrum fragmentation. This problem can be alleviated by introducing some order in the spectrum assignment process. Evenness in spectrum usage can be achieved by either limiting the size of the offered connections, or by using fixed bandwidth connections despite requests are of variable size. Based on the previous considerations, some approaches that mitigate spectrum fragmentation are proposed. Benefits in network performance achieved when applying these strategies are quantified by extensive simulations under different generated traffic conditions.