Power Consumption Testing - Some Figures

Care of my mates at Ixia’s test labs in Marlow recently, I took a few D-Link switches, including one from its Green Ethernet range, and ran them through Ixia’s IxGreen power consumption measurement suite.

Key here was D-Link’s “Green Ethernet” range submission – the snappily-named DGS-1224T Green Ethernet Web SmartSwitch (but none of the other vendors are any better at this naming game either). The smart bit here is that the switch reacts when a device attached to it is turned off, by placing the corresponding port in a standby mode that requires less power. Typically Gigabit Ethernet ports are always in enabled mode and consume power even when unconnected or not passing traffic. D-Link claims this feature can save up to 24% of the power used by a typical Gigabit Ethernet switch – something we put to the test – read on.

Using a real world traffic mix on the Ixia XM12 test chassis, running the IxGreen software, we tested each switch in turn initially at 0%, 50% and 100% loads with default gigabit mode enabled. In each case, we reran the test several times to check for consistency and took the average value – though there was very little variation between iterations, as we would expect. If you see the table below, you can see that the “Greenness” of the DGS-1224T shines through against D-Link’s other two switches in the test (which both recorded low consumption figures in their own right, as it happens). The results are in terms of total wattage recorded.


0% Load

50% Load

100% Load





DGS- 3426P








The consumption of the DGS-1224T amounted to less than a watt of power required to drive over a gigabit per second throughput – not bad, eh. And in “Green Ethernet” mode, power consumption was reduced from the already impressive 20.7watts (24 ports enabled, no traffic) to a truly outstanding 9.3watts. To put this into some perspective, most PCs consume more power than this in standby mode. These results really do show the benefit of being able to configure gigabit ports to be inactive by default – rather than the industry standard default of being active while ever the switch is powered up.

So, D-Link appears to be setting the pace for power reduction; where are the rest of you vendors? Game on…

Note: A full report on this testing will be available shortly both from the D-Link UK website and the Broadband-Testing website (www.broadband-testing.co.uk).