Navigating the WLAN Waters

Continually changing products and standards are adding confusion to the process of choosing wireless LAN products.

Keeping up with new developments in wireless LAN technology is getting tougher. The Institute of Electrical and Electronics Engineers Inc. seems to ratify a new and improved variation of its 802.11 WLAN standard every few months. Meanwhile, vendors announce round after round of products touting the latest enhancements -- sometimes even before the new standards are final. For IT managers looking to build anew or upgrade an existing WLAN, keeping abreast of the choices isn't easy.

"It's a lot of work to keep up," says Carl Whitman, executive director of e-operations at American University in Washington. Last year, Whitman finished a 13-month WLAN implementation based on 11Mbit/sec. 802.11b technology. Now he's considering converting the radios in some of his Cisco Aironet 1200 series access points (AP) to the 54Mbit/sec. 802.11g standard to boost throughput. But Whitman is taking his time sifting through the array of choices that have appeared on the scene since he first considered WLANs three years ago.

"New features and functions are coming at a staggering rate," says Ron Seide, product line manager for the WLAN networking business unit at Cisco Systems Inc. The good news is that Cisco and other vendors of enterprise-grade WLAN equipment are designing products that often can be upgraded with flash updates or add-in modules. "With software upgrades, you can push the configuration file change out to your access points without having to touch them again," Seide says.

Changing Channels

Vendors also offer hardware updates. For example, users of Cisco's 802.11b APs can convert to 802.11g with a $149 swap-out of the unit's internal radio hardware. Customers can upgrade units to 802.11a for $500. Cisco also offers Aironet client adapters that can run in 802.11a, b and g modes.

Ultimately, the ideal Wi-Fi architecture will be multiband, supporting both 802.11b and g (which operate at 2.4 GHz over three channels) and 802.11a (which operates at 5 GHz on up to 24 channels). Although 802.11a isn't backward-compatible with 802.11b clients, in the long term many organizations will need the extra channels available in 802.11a to support more users at a higher data rate.

But networks are still likely to continue to support devices operating in both frequency ranges. "It's not a 2.4 GHz vs. 5 GHz battle. It will be both, like an AM/FM radio," says Leigh Chinitz, chief technical adviser at Proxim Corp., a WLAN equipment vendor in Sunnyvale, Calif. "You will have b and g and a running, and it will be invisible to users."

Navigating the WLAN Waters
Image Credit: Lasse Skarbovik

A mixed 802.11b/g/a architecture may be the wave of the future, but not all product offerings are there yet. The current generation of wireless IP telephones, for example, supports only 802.11b. In the meantime, for many early adopters struggling to get a handle on all the changes, 802.11b works just fine.

Going With Plan B

At Scripps Health, a not-for-profit health care provider in San Diego, an 802.11b WLAN suits the needs of doctors, nurses, administrative staffers and patients just fine. "I don't know why we would migrate yet," says CIO Jean Balgrosky. Scripps is just finishing outfitting its five hospitals with WLANs -- a project that cost $30,000 to $100,000 per facility and included buying laptops, Aironet 1230 APs and a gateway to the wired network. Next on Balgrosky's agenda are Scripps' 12 community clinics. The ambitious WLAN implementation, which will also use 802.11b hardware, will be complete in August 2005.

802.11b throughput and reliability are sufficient to meet the needs of the various user groups, including nurses who have Wi-Fi-enabled laptops on carts that they roll from patient to patient, doctors who log in from home using their personal wireless devices and patients who surf the Web from their beds, according to Balgrosky. Although 802.11g APs don't cost any more than 802.11b APs, Balgrosky says she will stick with the latter so as not to add complexity to the network. It has sufficient bandwidth even for downloading compressed X-ray images, and she is loath to disturb the reliability and performance of the 802.11b-based architecture Scripps has been rolling out.

As WLAN security continues to advance, Balgrosky has kept up by adding a WLAN gateway. But she is wary of proprietary implementations that could lock her into a single vendor's products. So while Scripps uses WLAN equipment from Cisco, it has a wireless gateway from another vendor, Burlington, Mass.-based Bluesocket Inc. The gateway sits between the wired and wireless networks, providing authentication, encryption and role-based access to applications. "It gives us a lot of flexibility and doesn't lock us into one architecture or vendor as far as access points or wireless cards," Balgrosky says.

Picking standards-based technology is the key to her future-proofing strategy. "You can't know everything before you make a move. You have to be able to skate to where the puck is going," Balgrosky says. "We can shift without too much effort, once the bugs [associated with the latest standards] are worked out."

Because vendors like Cisco and Proxim build a level of backward compatibility into their hardware, upgrading from 802.11b to 802.11g doesn't generally require outside help. "It is relatively simple to upgrade, provided there is adequate documentation of what is deployed," says Tom Hagin, vice president of sales at NetXperts Inc., a WLAN systems integrator in San Ramon, Calif.

But there is one caveat for migrations to 802.11g. While the real-world performance of upgraded WLANs can average about 25Mbit/sec. when all clients run 802.11g, the performance of the entire network drops to 802.11b levels of 5M to 6Mbit/sec. when any 802.11b client device logs on. "When operating in mixed mode, there is a throughput hit associated with that backward compatibility," says Cisco's Seide. This can come as an unwelcome surprise if planners haven't anticipated it.

Sorting Out the Options

Beyond simple upgrade issues, many companies need help sorting through WLAN architecture alternatives. "We get a lot of calls to help people understand the ramifications of their choices," says Hagin. Security is always an important consideration, and most companies want a flexible architecture that will give them the option to run voice as well as data over the WLAN.

Voice over WLANs is a hot topic, especially in industries like health care, academia, public transit and manufacturing, which have been on the forefront of WLANs. Running wireless IP phones over a WLAN can reduce phone bills, especially for operational and building maintenance personnel who tend to be heavy users of cell phones or walkie-talkies.

At the other end of the spectrum, businesses in other industries, such as financial services, are only starting to investigate wireless. Only about 35% of Fortune 1,000 companies have deployed WLANs, says Stephen Elliot, an analyst at market research firm IDC. Most of those companies have finished wireless pilots and are pondering whether -- and how -- to wade in.

Companies with a blank WLAN slate want to pick network hardware that will be secure, easy to manage and able to evolve with future developments. For example, all new equipment should have a migration path for supporting the 802.11e quality-of-service standards (which should be finalized later this year) for future voice-over-IP applications.

Whether an organization is upgrading or starting from scratch, all decisions should flow from what will run on the WLAN. "Are you looking at a true multiservice wireless network that could include voice, data and possibly video? Who needs access? It all goes back to what applications you will be running," says Hagin. Integrators will conduct such assessments for a fee. For example, NetXperts typically charges between $1,600 and $60,000 for a comprehensive site survey. As part of the process, technicians set up a temporary wireless network and record room sizes and monitor signal strength while polling users to determine their bandwidth needs.

Companies also need to examine WLAN usage trends and security policies and procedures. And budget prioritization is a critical piece of any WLAN project. "You only have so much money that you can spend. You have to deploy certain areas before others, and there are political issues with that," says Todd Krupa, communications officer for information and access technology services at the University of Missouri-Columbia.

The university has an 802.11b network and uses Wavelink Mobile Manager from Wavelink Corp. in Kirkland, Wash., for centralized WLAN management. Krupa plans to upgrade 50 buildings to 802.11a in the next 12 to 18 months while continuing to run 802.11b in others. He doesn't expect the transition process to be a big deal for users, since students tend to arrive each year with the latest technology. "In 18 months, it is very likely they will have a/b/g notebooks, especially since those are already on the market now," he says.

Far bigger than the technology choices, Krupa believes, are the nontechnical issues. For example, since he's in a university setting, he can't control use the way a business might. "Those have to be campuswide decisions," Krupa says. He recommends having a wireless communications plan to convey usage and security policies and manage performance expectations.

IDC's Elliot agrees. "You need to do a deeper analysis of what this technology can bring. It's not always going to be positive," he says. "Those who don't get access -- or don't get it first -- are not going to be happy."

Paul is a freelance writer in Newton, Mass. You can reach her at

Copyright © 2004 IDG Communications, Inc.

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