Real-time power control for dynamic optical networks - Algorithms and experimentation

Core and aggregation optical networks are remarkably static, despite the emerging dynamic capabilities of the individual optical devices. This stems from the inability to address optical impairments in real-time. As a result, tasks such as adding and removing wavelengths take a substantial amount of time, and therefore, optical networks are over-provisioned and inefficient in terms of capacity and energy. Optical Performance Monitors (OPMs) that assess the Quality of Transmission (QoT) in real-time can be used to overcome these inefficiencies. However, prior work mostly focused on the single link level. In this paper, we present a network-wide optimization algorithm that leverages OPM measurements to dynamically control the wavelengths´ power levels. Hence, it allows adding and dropping wavelengths quickly while mitigating the impacts of impairments caused by these actions, thereby facilitating efficient operation of higher layer protocols. We evaluate the algorithm´s performance using a network-scale optical simulator under real-world scenarios and show that the ability to add and drop wavelengths dynamically can lead to significant power savings. Moreover, we experimentally evaluate the algorithm in an optical testbed and discuss the practical implementation issues. To the best of our knowledge, this paper is the first attempt at providing a global power control algorithm that uses live OPM measurements to enable dynamic optical networking.