Rethinking wireless: as wireless LANs grow on campuses across North America, academic technologists strategize for the challenges of the future

University Business, April, 2003 by Matt Villano

Remember when the only network on college and university campuses was the wired one? When schools Like yours invested millions in fixed Ethernet ports? When "network security" meant betting the house on the hope that outsiders wouldn't sneak onto campus and plug in? Those days aren't all that far behind us; even the pioneers in the wireless space didn't ditch their wires much before the current 802.11b wireless standards were ratified in 2001.

WHY WIRELESS

The academic wireless Local Area Network (LAN) has come a long way since then. Though few schools have advanced beyond expanding the networks they bought back in 2001, hundreds of schools across North America now have some form of wireless capability, and hundreds more consider it every day. The price of hardware necessary for wireless has dropped considerably, with access points ranging from $150 to $500 apiece, and network adapter cards as Low as $60. Last--but certainly not least--with the impending arrival of new wireless standards 802.11a and 802.11g, wireless technology will get faster and more secure, making even the harshest skeptics curious.

"Wireless is here, and it's here to stay," says Ron Yanosky, senior analyst with the Higher Education Technology Strategies Group at Gartner, Inc., in Stamford, CT (www.gartner.com). "When you consider that the modern college student is mobile most of the time, investing in a wireless LAN for your campus simply makes sense; you're investing in the technology that suits your users best." Still, as Yanosky points out, you can't just grow a multiple access-point wireless network overnight; the process takes time, planning, and careful execution. Experts and academic technologists all over North America agree that perhaps the three most critical steps in building a wireless LAN are designing the network, managing it, and securing it. After that, of course, the rest is up to you.

DESIGNING YOUR NETWORK

One of the biggest challenges in laying out a wireless LAN lies in designing the layout of the access points and ensuring that adequate coverage is provided throughout the service area. Since every access point has a range of roughly 800 feet in an open environment, the name of the game is stationing your access points to maximize coverage and minimize cost. While trial-and-error layouts frequently do the job, academic technologists agree that the most efficient designs are based on hard measurements, and not rule of thumb.

Of course, the coverage equation isn't as simple as plopping a new access point every few hundred feet. Because the coverage area of each access point is so small, terrain is not as much of a propagation issue as the layout and construction of buildings on campus. Wireless signals transmit perfectly through wood, plaster, and glass, but metal, brick or concrete walls have proven to be significant barriers. Compounding this problem is what experts refer to as the "contention-oriented" nature of the 802.11b wireless protocol. If one access point is too close to another, it will "defer"--that is, the point with the stronger signal will knock the weaker point offline, creating interference that impairs capacity and slows the network down.

"This technology is incredible when it's applied correctly, but there's so much working against it that many people actually hinder their own network coverage with poor planning," says Chuck Bartel, director of networks at Carnegie Mellon University, and project director of the school's wireless network (dubbed "Wireless Andrew"). To maximize coverage, Bartel suggests that technologists base network design on exhaustive signal-strength measurements, even utilizing an aid as sophisticated as SitePlanner from Austin, TX based Wireless Valley (www.wirelessvalley.com) or AirMagnet, a diagnostic from the Mountain View, CA, company with the same name (www.airmagnet.com).

AirMagnet is precisely the tool Todd Grappone used to design a wireless network up the road at the Stanford University School of Medicine in Palo Alto. When Grappone, associate director of Development for Stanford's Information Resources and Technology department, set out at the end of 2001 to build the School of Medicine's wireless network, an AirMagnet signal search revealed dozens of wireless access points on and around campus that students had set up themselves. To maximize coverage and performance, Grappone says he spent months taking over the "rogue," or independent, points. (The school took over support, and under the new wireless system provided free access to owners of the rogue points.) Thanks to these efforts, he adds, today it's rare that students access the wireless LAN at speeds less than 5 or 6 mbps. Of course, if the network-capacity needs of Stanford School of Medicine students change, Grappone will be ready to tweak his network design. Already, the wireless computing guru says that to meet growing demand in certain areas, he has repositioned a handful of access points from scarcely used meeting rooms to more popular lounges on and around campus. According to Yanosky, experts refer to this degree of responsiveness to student usage patterns as the "sidewalk paradigm."