Spectrum slicing-based fragmentation aware routing and spectrum allocation in elastic optical networks

For addressing the problems of high bandwidth blocking probability and low spectrum utilization caused by spectrum fragmentation in elastic optical networks (EONs), a dynamic EONs node architecture for deploying spectrum slicer is studied to transmit the request in the paper. The spectrum slicer can relax spectrum contiguity and improve spectrum fragmentation utilization for request's lightpath establishing. Then, a fragmentation aware routing and spectrum allocation based on spectrum slicing algorithm (SS-FA-RSA) is put forward. In the routing selection phase of SS-FA-RSA, a path weight value formula is designed to trade-off between path length, normalized fragmentation rate and available spectrum slicer, which reorder the candidate paths to select the most appropriate routing path for the request. Moreover, in the spectrum allocation phase, the spectrum slicing algorithm is proposed to increase the utilization of spectrum fragmentation by reusing spectrum fragmentation in EONs. Comparing with other algorithms, the simulation results show the proposed SS-FA-RSA can get better in bandwidth blocking probability and spectrum utilization.