How “Green” Is Your Network?

M. Spanbauer
M. Spanbauer

Summary Bullets:

  • You do not leave your lights on when you are not at home.  Why leave your network on when it is not in use?
  • Standards and products make possible 30-80% reductions in power used by network switches when idle.

Every port, every device, every wire plugged in consumes some amount of trace power.  While this awareness has been present for decades, only in the last five to ten years have vendors taken a close look at what can be done about it.  Initially, there were proposals and early standards that did make rough attempts at efficiency curves and requirements, sort of like ‘Energy Star’ for home appliances.  However, in the last year, a standard called Energy-Efficient Ethernet (EEE) has been finalized, and vendors have begun releasing products based on it.  In essence, the standard enables a switch port to go dormant and consume very little power by listening for a trigger signal that indicates data is coming or on the wire.  Few offices are occupied 24×7, and it does not make sense to have the port turned on fully on the switch side, just waiting for the transmission.  With some quick napkin math, it is apparent to many that this can result in significant energy savings over the course of a year.  Cisco, Juniper, HP, Brocade, Broadcom, and others support EEE in some platforms.

Whether by automated technology or by more cumbersome (yet still somewhat effective) policy-based software control that configures the switch, customers can save a great deal of money by enabling some energy conservation model or technology within the network when not in use.  If the network does not possess the control or capability to provide this granularity, the network itself may be consuming enough power to offset a portion of the cost of a network refresh in short order.  While this brief post is about the energy-saving benefits in the campus, there are even bigger savings that can be achieved in the data center.  The power profile of a data center and its infrastructure may yield five to ten times the savings of the campus. 

I can hear my father now: “Don’t forget to turn off the light.”

What do you think?

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