Eindhoven University of Technology PhD student Gonzalo Guelbenzu has developed strategies to shrink both datacentre energy consumption and required real estate. Focused on improving the network which interconnects all of the servers inside the datacentre, Guelbenzu reckons to process the same amount of data at half the energy consumption, and take up only one quarter of the space that is currently needed.
The first thing Guelbenzu did was to shrink datacentre switches. He demonstrated a prototype switch that can handle 4 x 128 ports, with a bandwidth of 5.12 Tbits/s, making it one of the most compact switches around the world.
In his set-up, Guelbenzu can fit four switches each consuming less power on the same rack surface which now hosts only one. “This means you can process four times as much information in the same space, while consuming only twice the amount of energy,’ he explains.
The main design choice the PhD student made was to integrate a different type of transceiver. “Standard switching devices have pluggable transceivers at the front-end, where the optical fibres connect to the rack unit. The front panel area limits the amount of transceivers that can be fit in,” observes Guelbenzu. “By using on-board transceivers positioned as close as possible to the switch’s processor, we can not only increase the amount of ports, but also reduce losses, since the electrical signal has to travel over shorter distances towards the switching chip.”
Secondly, the electrical engineer made an analytic model which is able to compare different network setups in terms of power consumption, cost, and the needed number of switches, transceivers and fibres. The model investigates the introduction of optical switching and WDM technologies into hybrid datacentres.
He used this model to estimate what would happen if current day photonic switches and WDM technologies were introduced into datacentre networks. “In case of 25 Gbits/s switches, which are currently getting more and more common in practice, introducing a maximum number of photonic switches leads to savings of 45% in switches, 60% in transceivers, 50% in fibres, 55% in power consumption, and 48% in cost.”
Finally, Guelbenzu demonstrated that the integration of these technologies is also practically possible by building a fully functional small-sized hybrid datacentre.