Tuesday, September 15, 2009

How green is your Ethernet?

The growing emphasis on energy efficiency in IT has led to plans to reduce the amount of power needed to run a corporate network by changing the way Ethernet switches and adapters work.
Here’s the idea. When a device connects to a network switch at present, it only ever negotiates the speed of that connection once, typically opting for the maximum bandwidth supported by both parties. So why not negotiate the connection dynamically, to enable the speed of the network port and the amount of power required to drive it to vary depending on the needs of the attached device?
For example, if a PC was idle, the switch could put its network port into standby mode. Similarly, it could configure a 10Mbit/s connection when the user was pulling down email and only opt for a full 100Mbit/s or Gigabit link when transferring large files.

Of course, the usual IEEE study group has been established to look into possible mechanisms for what is being called Energy Efficient Ethernet (EEE), but that will take a long time to report back, let alone come up with any concrete proposals or standards for developers to aim at. In the meantime, a number of the networking vendors are starting to talk up the concept, with D-Link going so far as to release products already with what it calls “green Ethernet” features.

It won’t be going as far as dynamically negotiating bandwidth, as that would require changes at the device end as well. However, D-Link’s Green Ethernet switches will be able to detect when attached PCs are turned off and power down the associated ports into a standby mode. They will also be able to analyse cable length and adjust power usage accordingly. And the end result could be savings of up to 44 per cent in terms of the overall power needed to run the switch, plus a longer product life thanks to a reduction in operating temperatures.

D-Link intends to deliver this kind of functionality in its managed switches, including the enterprise-grade xStack range, next year.

That is all very well, but cynics like me will question the use of the term “green” to describe this kind of technology. It’s a popular bandwagon on which to throw the concept and it could help save energy; however, to have a real impact companies would have to replace millions of Ethernet ports and that would come at a carbon as well as a financial cost.

I would also argue that simply by getting everyone to turn off their PC when they go home, we could make just as big a saving, if not more, and with none of the associated costs.

Src: http://www.whatpc.co.uk/itweek/comment/2200660/green-ethernet-3520628