Free to roam

Wireless local-area network (WLAN) technology may be on your shopping list as you start to provide less expensive, seamless network connectivity to employees who are moving cubicles, assembling in conference rooms or traveling between buildings.

WLANs also may allow you to extend wireless connectivity to contractors or other agency visitors by quickly assembling a network that can be easily dismantled once they leave. Growing buyer interest has attracted a range of vendors to the market.

Officials at the Defense Department's Joint Forces Command Joint Experimentation Directorate (J9) in Suffolk, Va., for example, are augmenting their wired network. By using a WLAN, they are providing wireless access to e-mail, other collaborative applications and voice over IP to 100 employees armed with tablet PCs, said Tony Cerri, engineering department leader at J9, which develops new warfighting techniques.

But the flexibility of the technology — and its ability to avoid the roughly $1,000 price tag that comes with wiring new cubicles — has prompted J9 officials to make a WLAN their primary network in a new campus building, Cerri said.

"I'm firmly committed to replacing the entire workstation structure...with tablet computers," he said.

WLANs, which use the 802.11 standard, allow mobile users to connect to their wired LAN via a wireless radio connection. To deploy a wireless network, first you need to equip client devices such as desktop computers, laptop computers and personal digital assistants with wireless network cards.

A device called a wireless access point connects to the regular wired office backbone and then communicates with wireless network cards installed in the client devices via radio signals, thereby connecting the two. Bridges to enable high-speed outdoor links between buildings might also be necessary.

Access points can cost as little as a few hundred dollars or as much as $700 for enterprise-grade products, according to Julie Ask, research director at JupiterResearch, a division of Jupitermedia Corp. Wireless network cards average about $40 to $50 when preloaded in a new computer or about $70 to $80 when added separately, she said.

As you shop for a technology vendor, you will find two camps. In one, companies such as Cisco Systems Inc., 3Com Corp., Proxim Corp. and Avaya Inc. offer intelligent access points to handle security and management.

In the other camp, wireless switch vendors such as Airespace Inc., Aruba Wireless Networks, Extreme Networks Inc., Legra Systems Inc. and Trapeze Networks Inc. move access point processing functions above the network's physical layer to a centralized switch for security, radio optimization and other management tasks.

Officials from LAN-switching behemoth Cisco are steadfast in their commitment to build on their installed wired base via an overarching technology framework. It promotes the integration of wired and wireless networks by adding mobility and other WLAN features to existing wired switches.

"A lot of times, customers don't necessarily have any experience in radio frequency," said Ann Sun, Cisco senior manager for mobility and wireless. They "want a solution that helps them to reduce [wireless networking] complexity...and make it as simple to manage as their wired network."

The distinction between the two vendor camps is starting to blur, because wireless switch vendors have begun to expand their product lines to support edge switches and the existing wired infrastructure.

Officials at wireless switch vendor Airespace, for example, recently announced a new WLAN appliance designed to connect to an existing Ethernet switch and create a radio frequency overlay for wireless management.

Extreme Networks officials have taken a similar path by offering switches that can provide wired or wireless connectivity. This approach allows network administrators to manage and secure access centrally at the switch.

Transmission security is another important issue to consider when shopping for WLAN platforms. Because the security and encryption built into the early variants of the 802.11 standard are vulnerable, many wireless vendors offer workarounds to bolster security. Many of these vendors are submitting the security features in their products for FIPS 140-2 certification from the National Institute of Standards and Technology.

Havenstein is a freelance writer based in Cary, N.C.

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