subject: Inefficient Ethernet wastes over $1bn a year posted: Mon, 05 Feb 2007 18:24:23 -0000
[Well, well - it seems all these droughts, floods, and tornadoes - or
was that flood, fire, famine and pestilence - are causing an outbreak
of common sense. Finally! - Stu]
Inefficient Ethernet wastes over $1bn a year
How non-green is your network?
By Bryan Betts -> More by this author
Published Monday 5th February 2007 07:02 GMT
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Energy saving has so far focused on PCs, servers and the like, but
now networks have been fingered as major wasters of power. An
industry group has claimed that Ethernet's poor use of energy could
be wasting as much as $450m a year - or 5.8TW-h - in the US. And
perhaps three times that much, worldwide.
The figures come from the Energy-Efficient Ethernet (EEE) Study
Group, a new body backed by the IEEE and the Ethernet Alliance, which
is charged with developing technologies and specs for Ethernet power
management.
A lot of the problem is connections running at higher speeds than
they need to, said EEE chair Mike Bennett. He added that the problem
has worsened as more and more systems - from business servers and
network printers to home IPTV set-top boxes - are left on 24x7.
"For example, measured at the wall socket, a device that operates at
100BASE-TX instead of 1000BASE-T when the link is operating well
under 100Mbit/s could save close to 2W," he said. "Multiply that by
two for the other end of the circuit and you're saving roughly 4W per
link. It may not sound like much, but over an enterprise with
thousands of links, it can add up."
He added that power wastage is going to get worse as Gig and 10Gig
Ethernet use ramps up. Early 10Gig server NICs burn as much as 24W,
but Bennett pointed out that most are also multi-speed and can auto-
negotiate, so there is the opportunity to cut power use by cutting
the connection speed when it's not under load.
"The key to all this is how much can be saved (ie. not wasted) with
technology presently on the market, and how much could be saved by
easily imaginable but not yet available technology," he said.
"We're going to look at ways to reduce power consumption by switching
to lower speeds during periods of low link-utilisation."
One challenge will be speeding up Ethernet auto-negotiation so it can
toggle between low and high speed quickly enough to handle bursty
traffic.
Several other organisations backed the EEE, including some that have
already done work on energy efficiency that could feed into the EEE's
specs.
"The ability to change speeds for power reduction is already present
in the EU code of conduct on broadband equipment for DSL," said Paolo
Bertoldi, a researcher with the European Commission. "Extending this
to Ethernet is a logical and important next step."
"We are interested in both the direct use of energy from networking,
and how being networked induces higher energy use in products," added
Bruce Nordman of the US Lawrence Berkeley National Laboratory.
Nordman acknowledged that while 5.8TW-h sounds a lot, it is less than
one per cent of total US electricity use. But as you reduce energy
use to manageable problems, most of these end up being under one per
cent, "so that fact is not especially relevant to whether it is worth
doing".
He continued: "The fact that network energy usage seems to be rising
doesn't mean that what we do to reduce the rate of rise isn't worth
it.
"We need to also look at the whole system - edge devices, NIC energy
(in edge and network devices), and the energy in the rest of the
network equipment, and optimise all of it." ®
