WLAN analyzers

Like a blind date, wireless LANs  can look attractive and compelling on the surface, but looks can be deceiving. WLANs might install smoothly with little forethought, but in time, they can represent huge problems, especially in terms of asset exposure and costs of computing services.

Doing your WLAN homework mandates using tools that can verify, audit and analyze a wireless network. Even companies that don't want a WLAN need an analyzer because of rogue installations. Many WLAN equipment vendors include site survey tools, either with their access point or client products - but these are often rudimentary, not standardized and not designed for the multiple phases of WLAN analysis.

WLAN analyzers usually consist of the same components used in WLANs: popular 802.11 network cards in either a notebook, handheld, or, in one case, a proprietary portable form factor. The handheld analyzers usually consist of software on an HP iPAQ PDA. And because they are mobile, the handheld devices are used less for protocol analysis than for WLAN-specific features, such as surveying radio channels for signal strength and device populations. The range of a handheld device is similar to that of notebook-based WLAN analyzers, except that a handheld device is much easier to wave in the air while looking for a signal.

We tested eight products (three handheld-based and five notebook-based analyzers): AirMagnet's
PDA and notebook versions; Fluke Networks' WaveRunner and OptiView wireless; Sniffer Wireless and PDA option; Network Instruments Observer; and Finisar  Surveyor Wireless.

The analyzers were tested on a dual 802.11b and 802.11a network (see How we did it ). During the tests, we found that each analyzer has a niche that its designers focused on. Only two products (the AirMagnet handheld and notebook version) had a strong WLAN generalist feel. The AirMagnet handheld, because of its mobility, wins our World Class Award over very tight competition from the Sniffer Portable and the AirMagnet notebook version. The Network Instruments Observer and Sniffer portable proved to be the best graft of wireless/radio analysis tools onto protocol analyzer platforms. Fluke Networks' OptiView with wireless option and Finisar Surveyor Wireless also were strong contenders, but each has a superset of features for WLAN use - and hefty price tags to match. Features in the other WLAN analyzers might still be attractive or even invaluable for certain types of WLAN analysis.

When they're good, WLAN analyzers are very good. When they're bad, it's only that they lack some competitive features. The units we tested also might be blindsided by new 802.11g technologies and nonstandard wireless LAN data rates found in "plus," "turbo" and other enhanced rates (see story ).