Energy-efficient resilient optical networks: Challenges and trade-offs

Energy efficiency and resilience are two well established research topics in optical transport networks. However, their overall objectives (i.e., power minimization and resource utilization/ availability maximization) conflict. In fact, provisioning schemes optimized for best resilience performance are in most cases not energy-efficient in their operations, and vice versa. However, very few works in the literature consider the interesting issues that may arise when energy efficiency and resilience are combined in the same networking solution. The objective of this article is to identify a number of research challenges and trade-offs for the design of energy-efficient and resilient optical transport networks from the perspective of long-term traffic forecasts, short-term traffic dynamics, and service level agreement requirements. We support the challenges with justifying numbers based on lessons learned from our previous work. The article also discusses suitable metrics for energy efficiency and resilience evaluation, in addition to a number of steps that need to be taken at the standardization level to incorporate energy efficiency into already existing and well established protocols.