Optical/IP Networks

Ethernet Gets the Power

Forget email -- why not use Ethernet to run your electric razor?

That's the kind of thing Cisco Systems Inc. (Nasdaq: CSCO) and others see happening with the advent of Power over Ethernet (POE), a topic that's been long discussed but didn't become universal until last June, when the Institute of Electrical and Electronics Engineers Inc. (IEEE) ratified the 802.3af standard (see Power Over Ethernet Approved).

Cisco affirmed its love for 802.3af earlier this week, announcing new products that carry backwards compatibility to Cisco's proprietary POE scheme. Cisco debuted 48-port Gigabit Ethernet linecards for the Catalyst 4500 and 6500 platforms and a 96-port Fast Ethernet card for the 6500 (see Cisco Supports Power Over Ethernet).

Linecards are nice, but with 802.3af in place, Cisco and others expect a stampede of more irreverent Ethernet devices like razors, not all of them using the network. Think about it. You're traveling to some country with alien, six-pronged power sockets. Instead of shopping for what you hope is the right power converter, you could bring an Ethernet-ready razor and draw power from any RJ-45 socket.

"Manufacturers need to build only one device, and it runs everywhere in the world with an Ethernet port," says Steven Shalita, senior product marketing manager for Cisco's Gigabit Systems division.

The razor idea is real; Shalita says he's heard of someone considering it. An even less practical (but way more bitchin') example is a guitar designed by Gibson Labs. It draws power from Ethernet and, according to Shalita, can be set for different pickup levels on each string.

When it comes to actual business use, Shalita sees more down-to-earth applications arising. "Fire protection, badge readers -- all of these things connect back to some kind of central system to monitor, and they need power to operate. You can run all of that from the LAN switch."

Cisco doesn't plan to build any of these devices, of course, but Shalita does see potential for the company's LAN switches to moonlight as a power supplies, giving Cisco the chance to perk up its boxes with POE-friendly features. One device definitely planned for production is a surveillance camera being developed by Sony Corp. (NYSE: SNE). But, given that 802.3af has been standard for less than a year, it's going to take time for many of these applications to emerge.

"We've heard of a few devices being developed -- sensor types of technology -- but we're not seeing broad deployment of those yet," says Duncan Potter, vice president of marketing for Extreme Networks Inc. (Nasdaq: EXTR). Note that the power delivered to an Ethernet client -- 12.9 Watts -- is not enough to run a laptop computer, but it could extend battery life significantly. And if battery technology continues to improve, who knows? "We've given the manufacturers of these types of devices a global standard and a number to aim at," Potter says.

Note also that 802.3af doesn't extend into carrier networks. Aside from the problem of distance, it's not practical to load up a system with enough power to run, say, an edge router.

Extreme supports 802.3af in its Summit 300 and Altitude 300 switches; and Foundry Networks Inc. (Nasdaq: FDRY) has added 802.3af to some of its BigIron boxes (see Foundry Intros Router, Ethernet Switch). But Cisco claims to be the only vendor making all of its switches POE-ready. Among other things, that means they're designed with space for the power supplies for delivering all this electricity. All 240 ports of the 4500 can support POE. The 6500 can support 500 ports of POE but can't deliver power to every port, because the power supplies can't provide that much juice.

The switches have been that way since their inception in 1999, but until now, they've implemented Cisco's own brand of POE, developed just for IP phones. Cisco's scheme delivers only 6.5 W to the client device. It also differs from 802.3af in the way the client device communicates with the switch, which is crucial because POE-powered devices have to tell the LAN switch that they want power. Cisco's discovery protocol was based on sending tones, while 802.3af dictates a resistance-based method.

This means it takes a little work to make an 802.3af device backwards-compatible with Cisco's scheme. "If the device can't speak that protocol, then the switch will never know to give it power," Shalita says. Naturally, all of Cisco's 802.3af products will have that backwards compatibility.

— Craig Matsumoto, Senior Editor, Light Reading

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