Performance evaluation of first-last-exact fit spectrum allocation policy for elastic optical networks

This paper evaluates the performance of the first-last-exact fit spectrum allocation policy for elastic optical networks. The first-last-exact fit spectrum allocation policy is intended to increase the number of aligned available slots and avoid small contiguous available slots, and hence suppresses the blocking probability. This policy separates the allocation of disjoint and non-disjoint connections. Connections with disjoint paths are allocated using the first-exact fit allocation policy, whereas connections with non-disjoint paths are allocated using the last-exact fit allocation policy. The separation of the disjoint and non-disjoint connections provides a higher number of aligned available slots. Simulation results show that the first-last-exact fit spectrum allocation policy improves the traffic admissibility compared to the conventional first fit and first-last fit policies.