07 March 2010

The Lessons of Wi-Fi #14: Wi-Fi Should Save Money, Not Waste It

The computer science graduate students shuffle into class, taking their assigned seats. The professor opens the lesson by asking if there are any questions about the assigned reading.

A student raises her hand and asks, "We live in such a complex world. How could it possibly have been created in just 7 days." Without a moment's hesitation the professor looks up and responds, "Because there was no installed base – it was a new deployment."

Retrofitting 802.11n Wi-Fi to an existing network requires consideration of a number of factors: switch capacity, cable length, cable capacity, power sources. The last item is especially important during the transition to 802.11n. Many 802.11n access points far exceed the current capability of existing
802.3af Power-over-Ethernet (PoE) sources. Some require an astounding 32 Watts or more, far beyond the capabilities of 802.3af.

Unless you read the fine print in product data sheets you could find yourself exceeding the power delivery capabilities of both power sources and a single Ethernet cable. A Wi-Fi network that was supposed to reduce the cost of IT infrastructure by doing away with unneeded wired ports and switches could instead result in a whopping big bill to replace PoE infrastructure.

The Lessons of Wi-Fi #14: a Wi-Fi network should save money, not waste it. If you have to add supplemental power injectors, especially mid-span power sources, labor and hardware costs will soar. Power-hungry access points and high-current injectors also generate a lot of heat, so you'll incur higher recurring cooling costs. And your carbon footprint will grow.

Aruba's 802.11n access points operate from 802.3af power sources. Always have. In fact, we were the first company to introduce an 802.3af powered 3x3 MIMO access point. The access points also feature a lifetime warranty because the company stands behind what it builds.

As you consider an upgrade to 802.11n, be certain that 802.3af delivers sufficient current to power all of the radios to their full operating mode in every access point. If the data sheet says you need something other than a single 802.3af supply operating over 100m of cable to get full performance, consider yourself warned.

So check out our range of
802.11n access points and leave it to someone else to relearn the lessons of Wi-Fi.