World Without Wires

Unless you completely avoid Starbucks and most major metropolitan airports, chances are you've come across wireless computing. Walk around those places and you'll notice laptop, handheld, and phone users enjoying untethered access to the Internet. Gradually, K-12 districts are following suit. According to the QED 2004-2005 Technology Purchasing Forecast, 14 percent of schools own wireless desktop or laptop computers, and 30 percent of districts planned to purchase wireless tech-nologies in the 2004-2005 school year.

Consider This

1. Why is wireless worth considering?

For starters, wireless networks offer mobility and flexibility: users of laptops, PDAs, tablet PCs, and wireless Voice over IP telephones can move freely about campus while staying connected to the Internet.

In addition, wireless networks are easy to expand—a plus for crowded districts with tough-to-wire portable classrooms. They're also an indispensable solution for older school buildings where asbestos precludes drilling into the walls to install cabling. Finally, technologists who have made the switch to wireless say that eliminating the costs associated with wiring a traditional network can save a district thousands of dollars.

2. How does it work?

There are two kinds of wireless networks: ad-hoc, or peer-to-peer networks, and wireless local area networks. With ad-hoc networks, each computer on the network has its own wireless networking interface card and can communicate directly with other wireless-enabled computers. The WLAN approach sets up a network connection that revolves around an access point. In this type of network, access points act as hubs, providing connectivity for all wireless-enabled computers within a certain geographic radius. With the help of a WLAN switch, the access points can connect a wireless network to a wired one, allowing wireless access to resources such as file servers and databases.

Wireless technology uses standardized radio frequencies to send data. The three most common standards are 802.11b, 802.11a, and 802.11g. 802.11b casts the broadest service radius, but it transfers information much more slowly than wired networks. 802.11a delivers faster performance than 802.11b, but it has a shorter range and is not as good at penetrating walls. The newest standard, 802.11g, operates in the same radio band as 802.11b but offers speeds comparable to 802.11a, making it perfect for high-bandwidth applications. By this time next year, industry experts expect a newer, faster standard: 802.11n.

3. How many access points does my district need?

Most access points can support as many as 30 computers concurrently, and each device services a finite range. Typical indoor ranges are between 150 and 300 feet, while outdoor ranges can stretch as far as 1,000 feet. The actual distance of these ranges varies in different environments. Complicating matters is signal strength: when operating at the limits of its range, access point performance drops precipitously.

With this in mind, solving the riddle of coverage is probably the trickiest part of wireless networking. Most districts determine how many access points are needed to provide reliable coverage through a WLAN assessment. Many IT companies and wireless resellers offer this service for a one-time consulting fee. If you're purchasing a WLAN switch, vendors such as 3Com, Cisco, and Proxim offer free network assessment software.

Another option is to implement "computers on wheels" technology. These portable wireless carts, known as CoWs, generally hold 10 to 15 laptops and one short-range wireless access point. Because each cart offers its own access point, some schools using them have scaled back on additional fixed wireless access points. Still others have reported that while CoWs improve mobility for teachers and students, fixed wireless access points with broader wireless range are still more reliable.

4. Once I've deployed my access points, how do they work together?

Since the newest Microsoft and Apple operating systems automatically search for active access points, you shouldn't have to do much more than plug in an access point for it to work (older operating systems can be retrofitted to work with wireless, too, but newer operating systems work best). What's more, because most wireless networking hardware vendors support the 802.11 standard, you can purchase access points from different vendors and still be able to connect. (Companies such as Roving Planet and WaveLink offer management software designed to work with disparate hardware.) Some companies sell access points as part of a broader wireless strategy that revolves around WLAN switches or routers and management software. These switches not only enable administrators to manage access points centrally, but also serve as a bridge to the wired network, enabling wireless laptop computers to communicate with computers on the hard-wired LAN.

5. Is a wireless network as secure as a traditional wired one?

At the end of the day, nothing is safer than a wired connection. Wireless networking poses potential security issues because intruders don't need physical access to the traditional wired network to gain access to data. For the most part, 802.11 wireless communications cannot be received or decoded by simple scanners or short-wave radios, but eavesdropping is possible using special equipment. There are protocols to protect against security threats. Perhaps the most common of these protocols is Wi-Fi Protected Access (to learn more, see "Secure Your Wireless Network" at www.techlearning.com).

Another big issue is the physical security of access points. Once these devices are placed throughout a facility or campus, they are susceptible to vandalism or theft. To combat this, a number of vendors offer multipurpose and lockable mounting brackets for access points so they can be affixed to walls and ceilings easily and securely.

6. Will a wireless network save me money in the long run?

Wireless networking certainly can save you money. The biggest savings associated with wireless networking are in overhead. By adding wireless connectivity to your network, the district can scale back on the amount of funding it earmarks to maintain (or grow) the wired network.

On the other hand, as with most new technologies, deploying a WLAN involves a considerable amount of work on the part of staff to manage upgrades and maintain the system. Another frequently overlooked cost associated with wireless is professional development. In that case, it's not so much training on the wireless equipment itself but training educators how to incorporate laptops into the curriculum. The best way to stay on top of all wireless costs is to plan ahead, both in terms of the physical growth of a network and network usage.

7. Couldn't I just replace my hard-wired network altogether?

With wireless you don't necessarily need your hard-wired network, but eliminating the traditional hard-line network might be imprudent. What if your access points are compromised by an intruder? What if, for whatever reason, a user simply cannot connect without the Ethernet cable? Although wireless is a wonderful luxury, the LAN is a mission-critical component of school district operations today. If you view wireless as a way to extend the wired network and not replace it, rest assured that one way or another, your network will be there.

Matt Villano is a California-based freelance writer who specializes in educational technology.