Wi-Fi technology is steadily expanding: IEEE 802.11a and 802.11g are now firmly entrenched alongside 802.11b, and (Wi-Fi Protected Access) (WPA) security is now accepted as a standard. Yet Wi-Fi compatibility between devices is still at an all-time low.
That’s what the folks at Wi-Fi Alliance tell me, at least, and they are best positioned to know because they test product interoperability between Wi-Fi access points, wireless cards, and software. The failure rate on 802.11b products alone, which have been well established in the market for at least three years, is about 25 per cent, according to Dennis Eaton, the Wi-Fi Alliance chairman.
Believe it or not — I say with tongue firmly planted in cheek — there are actually some companies that put products on the market before the Alliance lab gets its hands on it. To be fair, it should be noted that the Alliance charges between US$5,000 and US$12,000 for each product it tests. But all of those fees go directly to its five independent test labs worldwide. The Alliance’s payroll and expenses are paid for solely through membership dues.
The quickie solution might be to say you won’t put out a request for proposal unless it specifies that products carry the Alliance lab’s seal of approval. Unfortunately, that isn’t always possible, or practical.
I asked Eaton to identify some of the areas that should alert you to a potential problem. Among them, he noted that the number of Wi-Fi chip sets coming to market is increasing. That means buying new access points, even from your usual vendor, doesn’t guarantee interoperability with your current air cards because the latest model may be using a chip set from a different manufacturer.
Cost pressures – here’s another believe it or not – actually force vendors to cut corners, which may lead to lower-quality products that don’t stay on frequency as well as others. The 802.11g chip set is supposed to fall back to 802.11b if there are no other 802.11g devices available. That mechanism, what Eaton calls the “fall-back algorithm,” is not implemented well by all vendors.
Security is complicated, and it takes a lot of work to implement it right. If not done correctly, WPA and Wired Equivalent Privacy (WEP) may work on your device but won’t interoperate with other devices.
How else do all of these interoperability problems manifest themselves? The symptoms are quite similar. Performance and throughput may be compromised. If a user roams between subnets or moves even one foot in another direction and associates with another access point, the session may be dropped. Power-save protocol failures may severely reduce a notebook’s battery life, or sometimes the radio in the air card will shut down and won’t wake up.
Yes, Eaton tells me, all Wi-Fi devices are built to certain industry specs and standards. But like any recipe, they are subject to interpretation.
Next year, things promise to get even more complicated when Advanced Encryption Standard (AES) 802.11i is ratified and implemented in devices, and 802.11h is also added. The 802.11h moves frequencies around to stay out of the way of military radar. Today, all products also transmit at full power all the time. The 802.11h standard will limit transmission power to just enough to close the link.
While you can never be sure of 100-per cent uptime, asking the right questions may save you headaches down the road.
