Technology improvements that favor energy efficiency are gradually emerging in several areas. "As new generations of products hit the market, more of these kinds of features will be implemented," says Cosgro.
Some examples include more modular application-specific integrated circuit (ASIC) designs that allow switches to turn off components not in use, from LED panel lights to tables in memory.
Also, general advances in silicon technology will minimize current leakage and gradually boost energy efficiency with each new generation of chips. Eventually, says Cosgro, "we should be able to get networking equipment that uses 100 watts today down to 10 watts."
Improvements in other areas have also helped. Software, for example, is now more efficient, consuming fewer CPU cycles -- and less energy. And hardware is now designed to run at higher operating temperatures to reduce cooling costs.
For example, Cosgro claims that HP's current ProCurve equipment can run safely at temperatures up to 130 degrees -- higher than the specifications for most other data center equipment. "That's driven by requirements of IT managers who want to run data centers at higher temperatures," he says.
It may be possible to move to higher operating temperatures in a single-vendor wiring closet, but network equipment vendors will need to do a better job of testing in mixed environments before temperatures approaching 130 degrees can be sustained -- especially within racks in the data center. "No one knows how networking and other types of equipment will react when sitting next to servers that displace more BTUs," says Drue Reeves, an analyst at Burton Group. Today, each vendor tests with only its own equipment.
More sophisticated power-monitoring systems will also help save energy, as will management tools with more granular controls. Real-time power and temperature monitoring is key to any data center and is essential for managing growth. "If something is not right, you want to know about it before a catastrophe happens," says Rockwell Bonecutter, global lead of Accenture Ltd.'s green IT practice.
Management software could be configured to identify specific network equipment, such as voice-over-IP phones, by using the Link Layer Discovery Protocol. The software could then automatically shut off Power-over-Ethernet current for VoIP handsets at a specific time of day or when the associated PC on each desktop is turned off at day's end.
Another example: Edge switches are typically connected to two routers for redundancy during the day, but a network could be configured to have one router go into low-power sleep mode at night. The sleeping router would "wake up" only when or if it was needed.
These types of applications represent "a huge opportunity for savings," says Cosgro.