Control Plane Architectures for Elastic Optical Networks [Invited]

Network operators have deployed optical transmission systems in their production networks for several years. The transport technology for fiber-optic transmission systems in backbone networks has been a synchronous digital hierarchy. However, network operators started migrating such networks to deploy WDM systems to improve the utilization of the fibers. Network operators can migrate to 100 Gbps solutions that can cope with medium-term bandwidth needs. However, when evolving toward 400 Gbps or 1 Tbps, utilization of the optical spectrum is less efficient if the fixed-grid schemas are maintained. Elastic optical networks (EONs) are based on a flexible allocation of the spectrum and configurable transponders. There is an unprecedented flexibility at the optical layer, thanks to advances in the components to support EONs. To take advantage of such flexibility and unlock the potential of EONs, the control architecture plays a key role. This paper presents the architectural choices, including generalized multiprotocol label switching, path computation element, and software-defined networking using a transport application programming interface. Moreover, this paper presents how the open source Netphony suite enables the validation and testing of all previous control plane architectures for EONs.