Networking Gear Goes Green

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Energy-Efficiency Ratings

Finally, standardized measurements of energy efficiency have started to appear on some networking equipment. Juniper Networks Inc., for example, includes the Energy Consumption Rating on the data sheets for some of its products. ECR is a draft specification, created by the ECR Initiative consortium. Lawrence Livermore National Laboratory, Ixia and Juniper developed the specification, which measures performance per energy unit for networking and telecommunications equipment.

Both Cisco and Juniper are backing the Alliance for Telecommunications Industry Solutions' Telecommunications Energy Efficiency Rating specification, which ATIS introduced last year.

However, neither specification has been universally accepted. Juniper supports ECR but doesn't include the rating on all of its products' data sheets. Cosgro says HP hasn't included either of those energy-efficiency standards in its data sheets because users don't understand the metrics.

"What they care about is the number of watts used," he says.

Another strike against the specifications, Cosgro says, is that they lack a detailed, open rating methodology. That means vendors can choose rating firms that use methodologies that best suit their needs.

A truly open specification isn't likely to appear until next year at the earliest, when the Environmental Protection Agency starts work on an Energy Star rating for large networking equipment.

The agency announced an Energy Star specification for data centers in June and plans to eventually develop specifications for data center UPSs and cooling systems, according to a spokesman. These new specifications, which will cover everything from power supplies and internal chips to Energy Efficient Ethernet, will be "the key energy-efficiency standard" going forward, Cosgro says.

The easiest way to increase energy efficiency is to buy new equipment, but that's not necessarily a practical option, because network administrators making purchasing decisions must consider other factors besides potential energy savings -- such as the remaining useful life of their current equipment. A 15% cut in energy costs may add up when spread across thousands of servers, but the total savings would be much smaller on a few racks of switches.

Even for a single rack, the cost per kilowatt usually won't justify an upgrade. "Most people will not save enough energy in the short run to justify replacing their equipment," warns Burton Group's Reeves. "Stay on your regular life cycle."

Green Tips

5 Ways to Green Your Network

1. Refresh your equipment. Cisco estimates that the energy efficiency of its products improves 15% to 20% every two to three years. The energy savings alone aren't enough to justify buying new equipment, but improving efficiency is one of several reasons for keeping your refreshes on schedule.

2. Make use of energy-efficient features. These features can vary by vendor -- or even by model -- so check before you buy. For example, Cisco's Nexus 7000 switch can reduce power consumption in empty line-card slots, but that feature is not yet available in the vendor's more popular Catalyst 6500 series. Other vendors, such as Hewlett-Packard, allow you to turn off empty slots, but the process is a manual one. Juniper Networks lets administrators cut power to unused ports, but only by writing a script that lowers the power once a certain activity threshold is reached.

3. Virtualize. Server virtualization increases network utilization and reduces network equipment needs by allowing multiple virtual servers to share one or more network adapters within the confines of a single physical server. On the switch side, features such as Cisco's Virtual Switching System allow one switch to function like many, which means more than one server can connect to the same port. This works because most organizations overprovision switching capacity based on peak loads. Reducing the total number of physical ports required lowers overall power consumption. Similarly, HP's Virtual Connect technology abstracts HP server blades from Ethernet and Fibre Channel networks. It requires fewer network interface cards, reduces cabling requirements and increases network utilization.

4. Be careful with cabinets. Make sure networking equipment that goes into a hot aisle/cold aisle row uses front-to-back airflow, not side-to-side cooling. Vendors prefer side-to-side venting, which allows them to get more equipment into the rack, but units using a side-to-side design may blow hot air back into the cold aisle -- or directly into an adjacent rack, overheating it. If the vendor doesn't offer switching equipment that supports front-to-back airflows, you'll need to retrofit the cabinet with a conversion kit, available from vendors such as Panduit Corp. and Chatsworth Products Inc., which redirects it for use in a hot aisle/cold aisle configuration.

5. Use a structured network design. Your best bet for the greatest energy efficiency is to follow the Telecommunications Industry Association's TIA-942 Telecommunications Infrastructure Standard for Data Centers, says Rockwell Bonecutter, global lead of Accenture's green IT practice. The specification locates networking equipment in a main distribution area, which ultimately connects to servers, storage and other IT equipment in individual racks.

This version of this story was originally published in Computerworld's print edition. It was adapted from an article that appeared earlier on

This story, "Networking Gear Goes Green" was originally published by Computerworld.

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