December 31, 2010, 9:00 AM — Standards matter, but unless it's a new standard for Wi-Fi, the news that yet another has been ratified is usually a yawner. Not so with the adoption of the standard for energy-efficient Ethernet, or more formally IEEE 802.3az, which will lead to significant energy savings without a hit to performance or large up-front costs.
The new standard defines a protocol that lets two ends of an Ethernet network communicate only when they have packets to transfer. The protocol eliminates the overhead of typical administrative messages, allowing systems to stay in a sleep mode as much as 80% of the time.
"Systems can go in and out of the idle state much faster, and spend much more time in the idle state as well," says Wael Diab, a technical director at Broadcom and vice chairman of the IEEE 802.3 Ethernet working group.
Individual switches are likely to cut energy usage by as much as 80%, but there will be savings throughout the entire network. That's because there's a multiplier effect as devices higher in the stack are signaled to go into a low-power state.
How much retrofitting will be required to take advantage of the new standard? Because the standard covers just the physical layer of the stack, only adapter cards and switching hardware need to be swapped. However, as future standards begin to reference this standard, more complex software and hardware options will come into play, University of New Hampshire senior engineer Jeff Lapak tells our sibling publication Network World.
LAN links generally average less than 10% utilization; even at peak times, the utilization does not reach 100%. When data is not being sent, the lower-speed switches stop transmitting and consume less power. However, the higher-speed switches (1000Base-T and 10GBase-T), the ones that are relevant to data centers, continue to transmit actively when there is no data to send, and thereby continue to consume power when idle.