ISRS impact-reduced routing, modulation, band, and spectrum allocation algorithm in C plus L-bands elastic optical networks

C +L-bands elastic optical networks (EONs) cope with growing traffic demands by leveraging the C and L bands of deployed optical fibers. In this scenario, the inter-band stimulated Raman scattering (ISRS) becomes more serious and degrades the quality of transmission (QoT) of services, and should be considered to guarantee the lightpaths establishment for services in the routing, modulation, band, and spectrum allocation (RMBSA). In this paper, we propose an ISRS impact-reduced RMBSA algorithm that reduces the ISRS impact on services at the RMBSA process. In the routing phase, selecting the route with more available contiguous aligned frequency slots (FSs) and shorter transmission distance, the less ISRS impact of requests can be suffered and the spectrum resources of each link can be used as much as possible. In the modulation phase, the lower-order modulation format which can achieve the least required FSs and has higher OSNR tolerance is selected. In the band and spectrum allocation phase, allocation of higher-order modulation format requests to the C-band to reduce the ISRS impact from C-band to L-band. Meanwhile, centralized assignment of more required FSs requests to reduce the ISRS impact of these requests on other requests. Simulation results indicate that the proposed RMBSA algorithm can effectively decrease the blocking probability, improve the resource utilization and request average optical signal-to-noise ratio.