LoRB: Link-oriented resource balancing scheme for hybrid C/C plus L band elastic optical networks

Multi-band, especially C+L-band, elastic optical networks (EONs) provide a promising networking infrastruc-ture to increase the capacity of networks for alleviating the pressure on gradually increasing traffic load. Given the extensive new device deployments with time and economical costs, hybrid C/C+L band EONs would be a more realistic networking scenario during a long transition period. Apart from band expansion, fragmentation also needs to be addressed to enhance resource utilization, where links with more serious fragmentation should be concerned with high priority. This paper proposes a link-oriented resource balancing (LoRB) scheme in hybrid C/C+L band EONs, which allocates spectrum for lightpath request according to the minimum path contiguous available resource separation degree, incorporating both original and allocated value of each link along the route via a weighted approach. Note that the main physical-layer impairments in hybrid C/C+L band EONs are analyzed to estimate the signal-to-noise ratio of lightpath requests whether satisfies the threshold under different modulations in networks. Results indicate that the proposed LoRB scheme can reduce blocking probability and enhance resource utilization, compared with three benchmarks in hybrid C/C+L band EONs.