Greening the availability design of optical WDM networks

Tremendously increasing bandwidth demands on the Internet require high transmission capacity and reliable end-to-end connections which are offered by optical WDM networks. Huge bandwidth demands of the applications cause rising energy consumption at the optical cross-connects which contributes a significant portion of the total electricity consumption. In this paper, we study the availability design of optical WDM networks in an energy-aware perspective. We propose Power-Aware Reliable Design (PARD) for optical networks which is mainly based on two-step multi-hop lightpath bypass concept aiming to provision survivable demands with minimized power consumption. Through simulations, we show that our proposed approach, PARD can guarantee high availability levels for the demands with a significant decrease in power consumption when compared to a lightpath non-bypass availability maximization design. Moreover, it is also shown that employment of PARD is more fair than a lightpath non-bypass availability maximization approach in terms of deviation of per-node power consumption. We also show that increasing the spare capacity at the backup virtual links causes further decrease in power consumption while leading to a slight decrease in connection availability. Furthermore, we present that migrating to greener resources further improves the CO₂ emissions of PARD significantly.