Wireless at full throttle

Just as wireless LANs (WLAN) based on 11Mbps 802.11b (Wi-Fi) technology have started to catch on in the enterprise, vendors have begun shipping products based on the new 802.11a specification (Wi-Fi5, pronounced “why five”), which is two to five times faster, depending on transmission distance. And products based on yet another high-speed standard, called 802.11g, could be available as soon as mid-2003.

Confused? So are many enterprise IT managers, who have been left wondering which WLAN technology to deploy and whether a migration path will emerge that will let them preserve that investment in the future.

The specifications themselves may provide some answers. In addition to its faster 54Mbps data rate, 802.11a devices operate on eight channels as opposed to 802.11b’s three, reducing interference between the wireless hubs, called access points. It also uses a more efficient transmission technology that’s less susceptible to some types of interference. And 802.11a operates in the 5GHz frequency range, which is less crowded than the unlicensed 2.4GHz range used by 802.11b.

In contrast, the still very preliminary 802.11g specification could become a faster version of b, possibly boosting the data rates for the three b channels to 802.11a speeds.

Because a and b devices operate in different frequency bands, they can run in parallel. Some vendors already offer “dual mode” a/b access points that serve both client types. 802.11g, on the other hand, may be seen as more of a replacement for 802.11b. It will support b clients, but users probably won’t be able to flip the switch to g speeds until all b clients within range are upgraded.

Analysts say 802.11a adoption may be slow in part because the extra bandwidth isn’t a big draw for most enterprises, which typically use the technology in warehouse, loading dock and distribution centre applications. In the office, the technology is typically used as an overlay, rather than as a replacement technology for faster, wired Ethernet. Again, typical applications tend to be low-bandwidth ones.

Another issue is maturity. Most early 802.11a products are designed for home and small-business use, and the enterprise-class features are still evolving, says Ken Dulaney, an analyst at Stamford, Conn.-based Gartner Inc. The 802.11b technology still has more sophisticated management capabilities, and 802.11a isn’t yet approved for use outside the U.S.

Another consideration: While most applications are for handheld devices, 802.11a’s 32-bit bus architecture supports the Mini PCI and CardBus formats, but not the PC Card, secure digital or compact flash formats common on many handhelds.

Ken Pasley, managing director of wireless systems development at FedEx Services, the IT support unit of Memphis-based FedEx Corp., is cautious. “We’d like to move to a higher speed, like 802.11a, [but vendors] are really about six to 12 months away from having something we can do strong testing with,” he says. Pasley decided to deploy 802.11b for FedEx’s distribution centre and office applications and says he wants to see a “clear road map” for migrating from b before making any moves.

“Don’t even think about until mid-2003,” advises Dulaney. By that time, he says, “a whole lot of things will start to converge,” including the availability of better encryption and Wi-Fi5 interoperability certifications of 802.11a products.

But for now, “you have a lot of product out there. It’s half-baked,” Dulaney says. “Sit back, buy b, and don’t worry about it.”