Fairness enhanced dynamic routing and spectrum allocation in elastic optical networks

The finer spectrum granularity unit in elastic optical networks makes wider spectrum services more likely to be restricted by the constraints of spectrum continuity and spectrum contiguity (2SC), leading to higher blocking probability (BP). Obviously, it would deteriorate the fairness among multi-granularity services. Therefore, a fair dynamic routing and spectrum allocation algorithm is proposed. By virtualising the network resources as a ‘resource pool’, a two-dimensional rectangle packing model in combination with service holding-time is introduced to satisfy the 2SC constraints and to optimise the allocation of the ‘resource pool’ for dynamic multi-granularity services. Besides multi-granularity service fairness is achieved by tackling heterogeneous-size services together. Simulation results show that the benefit in terms of fairness can be reaped. Meanwhile, the authors also investigate the proposed algorithm's impact on performance metrics: namely, spectrum resource utilisation and BP. The results indicate that the proposed algorithm can achieve lower BP and higher spectrum efficiency.