Network operators cannot change their footprint to upgrade the entire network to support SDN from scratch. Hence, network operators adapted the original SDN concept into a hybrid SDN approach to have a pragmatic, evolutionary, and economically viable solution. This article tests an SDN architecture based on a hierarchical structure of a Software-Defined Transport Networking (SDTN) controller, which deals with the end-to-end service provision and topology collection on top of a set of SDN controllers for each technological domain.

We propose and demonstrate a set of microservice-based security components able to perform physical layer security assessment and mitigation in optical networks. Results illustrate the scalability of the attack detection mechanism and the agility in mitigating attacks.

This tutorial considers the evolution of SDN control for optical transport networks in disaggregated scenarios, focusing on its requirements and challenges when applied to "beyond 100G" networks - term that jointly refers to the use of coherent technology, data rates beyond 100G and the evolution of OTN standards to support rates such as 200G, 400G, or 800G.The tutorial cover suse-case driven SDN development, new challenges and requirements such as the need to account for physical impairments, multiband / SDM control, improved fault/alarm management, network sharing or optical telemetry and