Analysis of Performance Degradation in Sleep-Mode Enabled Core Optical Networks

Energy efficiency has been widely considered an important target for the management of Wavelength Division Multiplexing-based core optical networks, triggering signif- icant research efforts about the topic. A very interesting power management strategy for efficient optical networks consists on putting devices (transponders and regenerators) into a low power mode, called sleep or idle, or even turning them off, during low traffic periods. Such sleep-mode enabled transponders and regenerators yield to substantial energy savings; however, their non-negligible wake-up time may de- grade the network performance. Moreover, such degradation aggravates as more opaque is the architecture of the optical network, since more devices are affected by the wake-up time in the connections' end-to-end paths. In this paper, we evaluate how this affects the performance of the network depending on its architecture (transparent, translucent or opaque). Additionally, we propose a novel routing algorithm to mitigate the blocking probability due to the presence of the wake-up time. The benefits of the proposed algorithm are highlighted through extensive results.