On the Energy Efficiency of Optical Transport with Time Driven Switching

Reducing the Internet power consumption will become a challenging issue, since the Internet is expected to face a high growth in terms of traffic requirements. Simply scaling the network architecture, thus increasing its energy consumption, proportionally to this growth would not be a practical solution. Various energy-efficient approaches have been considered, typically consisting in a dual-layer network architecture through the introduction of an all-optical transport network layer, as relevant power savings can be reached thanks to optical technologies. Optical switching especially allows to significantly reduce the quantity of high power-requiring optical/electronic/optical conversions and electronic processing operations. A further improvement can be obtained with Time Driven Switching (TDS), a technique which allows to switch "fractions" of wavelengths directly in the optical domain exploiting the time-coordination of all network components. In this paper we show the benefits, in terms of power saving, provided by the TDS transport architecture, by performing a comprehensive overview of the different core network architectures and comparing the power consumption obtained in the different cases. With such an optical transport technology, power savings of more than 40% are demonstrated with respect to existing architectures.