Collaboration Leads to IEEE Standard to Reduce Energy Use of Internet-Connected Computers

October 20th 2010
Photo of the back of a PC desktop tower

The following article was written by Jon Bashor, Berkeley Lab's Computing Sciences Division.

A newly approved standard to help reduce energy use by networked devices was driven in part by an informal collaboration between energy efficiency and network experts at Lawrence Berkeley National Laboratory (Berkeley Lab). The standard, adopted September 30 by IEEE, the world's leading professional association for technology advancement, gives network managers and consumers of networking services the tools they need to reduce energy consumption in network-attached devices, network routers and switches, computers, and printers.

Bruce Nordman, a researcher in the Environmental Energy Technologies Division at Berkeley Lab, has long been examining the problem of energy use by idle electronics, including computers, printers, game consoles, and the like. Even when the systems are in sleep mode, they are still consuming—and wasting—energy. Nordman and his collaborator Ken Christensen, a faculty member of the University of South Florida, have developed approaches for cutting power consumption in idle devices.

The work was part of Nordman's research into making buildings more energy efficient. Electronics account for more than 10 percent of a building's electricity use, and more than half of this load (currently at least 150 terawatt-hours per year) is digitally networked, and the portion is rising.

About five years ago, Nordman learned that Michael Bennett, a senior network engineer in Berkeley Lab's Information Technologies Division, was involved in IEEE's (the Institute of Electrical and Electronics Engineers) Ethernet Working Group. Nordman called him, Bennett recalled, and said "We've got this idea…and it took off."

In 2005, Bennett was invited to speak at Google and was accompanied by other members of the IEEE working group. The topic of energy efficiency in networked devices came up and the wheels started to turn. Bennett arranged for Nordman to give a tutorial on his research at an IEEE plenary meeting in San Francisco. While some in the audience understood the importance of the work, many others did not. "Most network chip designers weren't focused on energy use back then," Bennett said.

Nonetheless, under IEEE's procedural rules, a study group was formed to consider developing a standard, and after more than six months, a project was authorized. This led to the formation of the IEEE 802.3az Energy-Efficient Ethernet Task Force, which Bennett chairs.

The task force considered two different approaches to address the issue. Nordman's proposal was to have networked devices automatically switch to lower speeds when not in use. The other idea was to have the devices go into low power idle mode. Ultimately, the low power idle mode was adopted by the task force, but Bennett credits Nordman with the inspiration for the task force and believes his approach will continue to be influential (it has been referenced by the U.S. Environmental Protection Agency's ENERGY STAR program).

"It really was a classic example of collaboration," Bennett said of the interactions with Nordman. "It really speaks to the openness and collegiality of the Laboratory when a researcher in one division can pick up the phone, call someone he hasn't met, and this leads to productive research."

The new IEEE 802.3az Energy-Efficient Ethernet (EEE) standard defines mechanisms and protocols designed to reduce the energy consumption of network links during periods of low utilization, by transitioning interfaces on computers and network switches into a low-power state.

When IEEE 802.3az compliant products have been fully deployed in new and existing Ethernet networks, it is estimated that power savings in the U.S. alone could reach 5 terawatt-hours per year, or enough energy to power 6 million 100-watt light bulbs. This translates into a reduction of the Information and Communication Technologies (ICT) carbon footprintby roughly 5million tons per year.

"The great advantage of using products supporting EEE is that there is no complex configuration necessary," Bennett said." In most cases, energy will be saved automatically."

Jon Bashor