On-Off IP-over-WDM Networks: Daily Power Consumption Analysis of Bypass and Direct-Bypass Design Approaches

We compared the energy efficiency of Multi-Layer Bypass and Direct-Bypass design approaches when addressing daily traffic variation. On-Off dynamics save up to 47% with respect to peak-hour traffic. The Bypass design outperforms the Direct-Bypass of up to 9% at IP layer and up to 21% at WDM layer for 100G coherent networks. Introduction Satisfying the overall clients' demand is not the only constraint network designers have to deal with. Given today's "green thrust", in addition to deploy new low-consumption devices, designers should also consider that energy can be saved by switching on/off devices according to client demand variations 1 . In fact, during the day a 60% reduction at off-peak hours can be observed 2 . Since the mean traffic is about 70% of the peak value, networks can be thought of as 30% overprovisioned on average. As for Multi-Layer design of IP-over-WDM networks, Bypass (Bp) and Direct-Bypass (DBp) approaches have been introduced 3 . They require intelligence at optical node enabling IP traffic, whose destination is not the intermediate node, to directly bypass the intermediate router via optical switching. Bp can also exploit IP processing at intermediate nodes for traffic grooming purposes whereas DBp cannot. In our study we add the complexity of dealing with limited transmission reach (i.e., need for signal regeneration). As for with DBp it can be achieved via 3R regenerators while Bp can also exploit the IP processing at intermediate nodes In 1 authors consider transparent (no impact of physical impairments) networks and they switch on/off of devices only at IP or WDM layer.