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It's a familiar image: eager volunteers dressed in blue jeans
and work shirts, pulling network cable through suspended ceilings
in schools across the country. Today, however, that well-known
Category 5 cable is getting some competition from radio waves:
School districts are discovering that installing a wireless local-area
network (LAN) is becoming a cost-effective option for extending
Internet access to all classrooms.
Wireless LANs have always boasted advantages over cable in terms
of ease of installation, but as prices have fallen, educators
have identified many additional benefits. For starters, wireless
LANs can help stretch limited technology dollars by allowing flexibility
in the deployment of computers in a school. What's more, many
educators have found that the freedom of movement provided by
wireless-equipped laptops fits well with student-centered and
constructivist teaching methods.
Wiring a school the old-fashioned way with cable is a fairly
easy task in the case of buildings that were constructed during
the past two decades. But schools built in the earlier part of
the 20th century often have foot-thick cinder block walls between
classrooms, and ceilings made of solid plaster. Sometimes, asbestos
is an additional concern. Wiring these schools is beyond the scope
of NetDay volunteers and can present many problems that are costly
for wiring professionals to solve.
Even when a school building's structure does not present too
many complications, the prospect of wiring every single classroom
with multiple network drops often just isn't practical. As a result,
network access in a school often is limited to a computer lab
and a couple of classrooms with a few computers in the back. This
limitation can be a real roadblock to the efficient integration
of network resources into the curriculum by all students. Clearly,
having ubiquitous network access available to every classroom
on an as-needed basis would be an ideal situation for most schools.
Wireless networking can provide a solution to most of these
problems.
With a wireless LAN in place, notebook computers can be carried
from classroom to classroom while connected to a seamless, school-wide
network. Stubborn cinder block and plaster are no impediment.
In a typical wireless LAN setup, schools install wireless access
points -- two-way radios for data -- close to areas where network
access is desired. Depending on the technology used, these transmitters
can be as far as 500 feet (and in some cases, even farther) from
the computers that access them, giving educators the option of
placing the access points in areas that are easier to wire. Each
access point must then be wired to the main network, and each
computer must be outfitted with a wireless card. This 500-foot
wireless connection can make a world of difference in older schools
with complicated wiring problems, and it can save schools the
trouble of placing countless network plumbing drops in classrooms.
Just-in-time network
By freeing computers from network cables in this manner, the
Lancaster County School District in Lancaster, S.C., has been
able to spread network and Internet access where it's needed --
and most important when it's needed.
"Our classrooms are older, the rooms smaller," says Smith McDonald,
the district's computer specialist. "You can't really fit computers
into the room when there's a whole class in there." McDonald installed
a total of 20 RadioLAN
wireless access points ($999 each) throughout the middle school
last year and deployed 40 notebook computers on wheeled carts.
Each of the notebook computers has a $499 wireless networking
card that communicates with the access points.
"When a class needs computers, we wheel them in," McDonald says.
"When they don't, they're moved to another room." Besides making
the most of physical resources, the mobile cart allows teachers
to determine when they'd like to use class-wide computing -- and
to remove it when they believe it would be a distraction.
"We're in the process of making this available through all the
schools," McDonald says. "After all, how many students can you
serve in a few computer labs? How do you schedule student time
in them? We've found this the best solution for the teachers and
the students when integrating computing into the curriculum."
Wireless technology can provide flexibility in other ways, too.
In one district, administrators found that their wireless LAN
could be extended to a classroom annex.
"We had a field house, out across the parking lot, that needed
network access," explains Art Rosenberg, supervisor of vocational
education at Garden Grove Unified School District in northern
Orange County, Calif. "The field house was converted to a computer
lab, and we used it primarily to teach computer classes and computer
repair. Without wireless networking, we'd have to dig across the
field and dig up part of the parking lot to lay cable. With the
wireless connection, we're online and hooked to the main school
LAN with no problem."
Turn on, tune in
As you look at the variety of available wireless LAN solutions,
you'll find that range, speed, and power consumption are some
of the most important issues. Often, greater speed is achieved
with a tradeoff in range, and vice versa. Many wireless cards
offer speeds around 10 Mbps range, which is more than adequate
for Internet access and network file sharing. You might pay for
the speed in terms of power consumption, however, as the use of
wireless cards in laptops can require recharging the laptop's
batteries more frequently.
Keep in mind that your school's construction plays a big part
in how much range you're likely to get from your wireless LAN.
Buildings with many girders, thick walls, and concrete will shorten
the effective range. For that reason, it's always wise to try
out a few different vendors' solutions to see how well they perform
in your environment. Another factor that can limit range is interference
caused by portable phones and microwave ovens, which often use
the same frequency band as wireless LANs. If an access point is
located too close to a teacher's lounge or a cafeteria, performance
might suffer, although some wireless technologies are better at
rejecting interference than others.
Wireless networking technology is available in a variety of
often-incompatible standards and speeds, so sticking with one
wireless vendor is a good idea. Virtually all modern laptops come
equipped with a PC Card (formerly known as PCMCIA) slot that can
accept a wireless networking card. But as with any computer peripheral,
it's wise to check with the wireless vendor and the notebook vendor
to make sure the two devices are compatible.
Wireless can make sense for desktop computers, too. Most vendors
provide add-on cards for desktop computers that allow educators
to mix notebooks and full-size computers on the same wireless
network. Depending on the vendor, up to 50 users can use one access
point.
Because wireless technologies emphasize portability, the use
of handheld computers can also be a logical move. In California's
South Pasadena Unified School District, school officials have
combined wireless LANs with ultraportable handheld computers and
thin-client network access in the classroom.
The district's high school uses Windows
CE-based handheld computers in the classroom to access the
Internet. The district chose the small, light IBM WorkPad Z-50,
which works well with Proxim
RangeLAN cards that are made especially for Windows CE devices
and draw very little battery power, says Curtis Lee, director
of instructional technology for the district.
"The larger Windows CE devices have a good-sized screen, they're
light, and now wirelessly connected to the Internet and our school
network," Lee says. The one drawback is lack of speed, which is
limited to 1.6 Mbps and can slow down routine Internet use depending
on the number of users on the access point. "But with the IBM
WorkPad Z-50 we're getting up to 12 hours battery life," Lee says.
"The WorkPads are light -- under 2 pounds -- and the 9-inch screen
is adequate for most applications, including e-mail and Internet
usage." The price is also right -- under $700 per device, or nearly
half that of a notebook computer.
Cost-effective solutions
Wireless LAN technology is becoming increasingly affordable
to schools. Apple Computer's iBook
laptop, introduced last fall, offers built-in support for inexpensive
wireless networking. With the addition of a $99 AirPort
adapter card, the iBook can communicate wirelessly with Apple's
$299 network access point, the AirPort Base Station. Apple's AirPort
technology can also be fitted to the company's new G4 and latest
iMac desktop systems. Although the range is limited to 150 feet,
the speed -- up to 11 Mbps -- is roughly equivalent to the speed
of traditional wired Ethernet LANs.
This might still seem pricey compared to $20 traditional wired
Ethernet cards, but think of the money saved on wiring -- and
the deployment flexibility gained by being able to move computers
from classroom to classroom.
"Wireless is very cost-effective in other ways," Lee says. "By
using thin-client access wirelessly, I can use the Windows CE
devices to log onto our network as Windows NT clients." Because
most of the processing is performed by the server, the wireless
handheld computers can be made relatively inexpensive. "And these
wireless devices allow students to enter the school campus as
an entire cocoon of networking -- they can freely roam the campus
and have access, no matter where they are, from classroom to classroom,
under a tree, in the lunchroom."
The aim, he says, is to give students access to the network
anywhere and at all times, as easily as possible, from highly
portable information devices. As with all things electronic, more
power for less money is the future of wireless networking, Lee
says: "These smaller, wireless devices should be in the $300 range.
When they are, universal access to the network is a reality,"
he said. "There's no question it will be available to every student,
at all times."
Indeed, what began as a convenient way around wiring hassles
and drilling through cinder blocks might ultimately become the
path to universal, always-on network access for schools.
Steve Bosak
is a freelance technical writer in Batavia, Ill.
(Editor's note: For more information on wireless
technologies, see Internet Unplugged,
January 1997.)
SELECTED WIRELESS LAN VENDORS
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