Ethernet: Getting Faster, Getting Greener

With enterprises scrambling to find ways to cut energy costs, one
less-obvious way may come in the form of Ethernet — that venerable,
ubiquitous networking technology.

While already pervasive throughout the enterprise, Ethernet is
continuing its march forward with new initiatives that could mean far
faster connectivity for all network users while still being “green” — with
greatly reduced power requirements.

“In a standard data network … you’re not worried about power
savings,” Brad Booth, president of the Ethernet Alliance industry
association, told “Pre-2008, we didn’t care how
much power we used as long as we were able to communicate the data.”

But with today’s greater focus on power savings, networking vendors are
caring how much power everything uses. That’s where an innovative use of an
existing Ethernet standard comes into play.

As part of a student white paper challenge sponsored by the Ethernet
Alliance, University of South Florida student Francisco Blanquicet came up
with the concept of using the pause cycle in Ethernet to turn data flow on
and off, thereby saving power.

“Originally, pause flow control was set up to prevent switches from
swamping end nodes,” Booth said. “If you have a server or a desktop and it
can’t handle the amount of data coming into it, Ethernet can pause the
flow. When that standard was written people started using it, but then
found it didn’t work with certain types of traffic very effectively.”

Booth described the pause flow control approach for reducing power as
an interesting use of an existing technology. Since pause flow control is
already part of the Ethernet standard, it can be readily implemented by

The approach could result in a 10 to 15 percent reduction in power,
Booth estimated.

To drive even greater power reduction for Ethernet, the backers of the
networking technology are also busy undertaking a new standards effort,
Energy Efficient Ethernet. The goal of Energy Efficient Ethernet is to
reduce Ethernet power consumption by 50 percent or more.

“One of the things they’re looking at is to actually shut down and
literally, physically turn off the physical layer device for a period of
time and allow the device to take the line quiet,” Booth said. “Then bring
it up for a refresh every once in a while. By refreshing intermittently, it
allows you to wake up quicker.”

Additionally, Booth said Ethernet’s supporters also examined reducing
speeds from 10-gigabit Ethernet (10GbE) to 1GbE, based on network demand —
though the results proved less than promising.

“What was discovered is that shifting speed actually took so long that
you would notice the impact on your network and you could potentially lose
packets,” he added.

10GbE itself also continues to evolve. At Interop this year, the
Ethernet Alliance is demonstrating how 10GBASE-T can be transmitted over
Cat6a cabling to a distance of 100 meters — nearly double the technology’s
55-meter transmission limit a year ago.

While 10GbE is currently the top speed for Ethernet, the race has
already begun for 40GbE and 100GbE speeds, through the IEEE High Speed
Ethernet effort, an initiative that Booth said had been incubated by the
Ethernet Alliance.

Those pushes mark only some of the most visible efforts by the Ethernet
Alliance, which spends much of its time between IEEE meetings to build
consensus proposals.

“The big thing with the IEEE is building consensus, and the Ethernet
Alliance is supporting that effort, making sure that consensus building is
happening,” Booth said.

He added that Ethernet Alliance member are already talking about
showing 40/100 GbE equipment in 2009.

With Ethernet getting greener and faster, there are still areas that
may need improvement, however.

“Ethernet is a prevalent technology and it still spreading its wings
into areas,” Booth said. “We have to sit down and honestly say to ourselves
where can we improve the technology and make it better for next generation
of datacenter and the Internet in general.”

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