Power Over Ethernet Will Be Part of Your Future

POE will fundamentally change the way wireless networks and voice-over-IP telephones are implemented, writes eWEEK's Cameron Sturdevant.

Power over Ethernet, the 802.3af specification published this summer, should be on the shortlist of new technologies that IT managers in nearly any size organization implement in the next two years.

I dont say "immediately" because significant infrastructure changes, including running additional power to the wiring closet, must precede the implementation of power-delivering Ethernet switches.

Without underplaying the significant facility changes I outlined in my Nov. 24 tech analysis of the 802.3af specification, I want to be clear: POE will fundamentally change the way wireless networks and voice-over-IP telephones are implemented.

For example, Cisco has already shipped more than 16 million ports of its pre-802.3af in-line power implementation. Steve Shalita, senior manager at Cisco, said in a recent telephone interview that he was unable to discuss plans for the release of new 802.3af-compliant line cards that would work in current Cisco chassis. However, it was clear from our discussion that such cards are under consideration.

Its also clear that IT managers are the beneficiaries of Ciscos decision to embrace the IEEE standard, instead of continuing to advocate for the in-line power implementation that the company developed. The adoption of the IEEE standard clears the way for IT managers to work hard to ensure that the nitty-gritty infrastructure changes—such as running additional electrical power to wiring closets and ensuring that those closets have enough reliable backup power—are made as quickly as possible.

The gamble, which I think is worth taking, is that POE is going to spawn a slew of new power devices that will only increase the central role of IT in providing cost-effective services that show up on the bottom line. This is a gamble because its impossible to say what these new applications will be, but here are some of my best guesses, based on discussions Ive had with POE experts at Texas Instruments, Extreme Networks, Hewlett-Packard and PowerDsine.

Its very likely that well see new kinds of sensors all over the place. From the factory floor and walk-in freezers to HVAC equipment and security-badge readers, new low-power, easy-to-install devices will start to pop up wherever IT can run an Ethernet cable. One reader responding to my Nov. 24 analysis rightly said that IT managers will need to become diligent about the safety of these new devices, especially when installing PDs in the plenum space above ceiling tiles.

This is certainly one thing that until now, licensed electricians took care to ensure safe device placement because the electrician was also running the power to the new location. In fact, I recommend that IT managers continue to use highly qualified electricians to run powered Ethernet cables to support devices wherever they are used in a facility. Because Ethernet cable is far easier to install than electrical cable, having a professional pull the wire is still less costly than having an improperly installed wireless access point start a fire.

Aside from safety concerns, IT managers still have weighty decisions to make regarding POE implementations. Ciscos Shalita made it clear that in addition to the power classification included in the 802.3af spec—four amounts of power that a PD can signal to the powered switch that it will need—IT managers will need to consider proprietary extensions that support power management.

For example, according to Shalita, some Cisco IP telephone handsets use the lowest amount of power, about 2 watts, while sitting idle. The handset uses the most power while it is ringing and a different amount of power during a conversation. The ability of a powered switch to recognize the difference in potential power consumption, and even the daily pattern of power consumption, will certainly be a factor in the economical operation of powered switches.

The POE standard will change the way IT deploys big applications. For many IT managers, starting now to plan for POE will pay dividends later.

Senior Analyst Cameron Sturdevants e-mail address is cameron_sturdevant@ziffdavis.com.