Analysis of performance degradation in sleep-mode enabled core optical networks [invited]

Energy efficiency is an important target for the management of wavelength-division-multiplexing-based core optical networks. A possible power management strategy for energy-efficient optical networks consists in putting opto-electronic devices (transponders and regenerators) into a low power mode, called sleep or idle, or even turning them off, during low traffic periods. It has been shown that sleep-mode enabled transponders and regenerators yield to substantial energy savings; however, their nonnegligible wake-up time may degrade the network performance in terms of the blocking probability of the connections. Opaque networks, in which transponders are utilized at each node in the end-to-end path, are especially prone to such degradations since multiple network nodes may simultaneously exhaust their pool of transponders due to long wake-up times, increasing the blocking probability. On the other hand, these degradations are less severe in transparent networks. In this paper, we evaluate how the duration of the wake-up time affects the performance of the network in terms of blocking probability depending on its architecture (transparent, translucent, or opaque) and the dynamicity of the traffic. Additionally, we propose a novel routing algorithm to mitigate the blocking probability due to the wake-up time. The benefits of the proposed algorithm are highlighted through extensive results.