Education

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Educational settings from elementary schools to college campuses are turning to WLANs to provide network and Internet access. In fact, some of the largest active Wi-Fi networks in operation today are installed at campuses such as Howard, MIT, and Stanford. A late 2001 NOP World Technology survey conducted on behalf of Cisco Systems discovered that 35% of educational institutions in the U.S. have already implemented wireless networking in their organization. (For full copy go to newsroom.cisco.com/dlls/tln/pdf/WLAN_study.pdf.) This is far higher than in any other vertical industry. The reason for such growth is simple. The use of wireless LANs helps financially constrained institutions achieve more while staying within their budget. It allows them to introduce, at a very reasonable cost, leading applications, like e-learning, that enhance the learning experience.

The survey also discovered that the benefits of Wi-Fi in the educational sector were based around mobility, convenience, and flexibility. The ability to quickly deliver networking services anytime, anywhere without the need for cabling, is Wi-Fi's most distinguishing feature. (See Fig. 15.2). When translated into an ROI calculation across all industry sectors, the survey found that this represented a $550 savings per user, or an average $164,000 annual cost savings—not including ROI from productivity gains.

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Figure 15.2: Percentage of educational IT managers who perceived benefits from wireless LAN technology. Graphic courtesy of Cisco Systems.

However, Wi-Fi's momentum in the educational arena was initially brought about because many institutions have buildings that are difficult to reach or expensive to cable. Most of such locations don't have connection to the school's network, because there is no physical link between the central network and the networks serving these outposts. Or, if linked, it's via an expensive leased line.

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THE UNIVERSITY OF TWENTE

This Netherlands university has built a Wi-Fi network, with the help of IBM and Cisco Systems, that extends over the school's entire 346-acre campus. The WLAN supports 6000 students and 2500 staff members. The network uses 650 Cisco Aironet 1200 series access points, and while most of the network uses 802.11 b, there are sections run on 802.11a.

With a WLAN as part of the networking mix, the wired LAN infrastructure is minimized; it is only needed to support the necessary virtual LAN connections and APs in the classrooms and elsewhere.

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Today's WLANs allow a scalable connection with any wired network infrastructure. Technology is also available that can enable students and faculty to roam about the campus while maintaining a stable network connection. Above all, retrofitting older buildings with networking using wireless technologies lowers the overall cost of ownership and facilitates faster installation. And, except for connecting the WLAN's access points, physical wires are not needed.

Wireless Bridges

As discussed in detail in Chapter 9, wireless technology can bridge buildings so that a single network can cover an entire campus. A wireless bridge not only provides connectivity, it also reduces server hardware and licensing costs, as well as bringing about a reduction in the management activity needed to build, monitor, and maintain multiple networks.

A WLAN also offers greater flexibility than its wired counterpart. For instance, there is a national shortage of classrooms, which is often addressed through the use of trailers configured as mobile or temporary class space. Although these temporary structures have heat and light, they often don't have access to the school's network or the Web. Schools that do make the investment to provide access often do so via a fiber-optic network link, which can be expensive (often costing at least $5000). Furthermore, the fiberoptic link has to be run each time a trailer is added or moved. Since trailers are modular, they are often moved, resulting in recurring recabling costs.

Wi-Fi, however, provides a better method. A single access point usually is sufficient for a number of classrooms, or an access point could be used to connect temporary classrooms, remote from the main building housing the central network. Thus, simply placing an access point and antenna near a window of the main building allows connectivity across, for example, a playing field to outlying buildings.

As discussed at length in Chapter 9, buildings at a greater distance can be connected using a bridging solution. Even if you can't see the other building from your window, a mast from the roof may provide the line-of-sight required for this low cost solution.

And if you need your network to reach outside your campus, Wi-Fi can also connect facilities within a specific geographical region. There are many wireless bridge products that can link networks and provide fast, cost-efficient integration of remote sites and end-users. Wireless bridges provide line-of-sight bridging at distances of up to 25 miles (40.2 kilometers) in FCC regulated countries, or 6.5 miles (10.5 kilometers) in the EU countries.

A wireless point-to-point or point-to-multipoint bridge can connect remote campuses, research field sites, and even community facilities to provide community-wide information, learning, or research networks. The technology also enables multiple buildings to share a single high-speed connection to the Internet, without cabling or dedicated lines. In addition, wireless bridges lead to the complete removal of recurring leased lines expenses, delivering tremendous financial benefits.

Mobile Carts

If space is limited and setting up computer labs is impossible, you may find that a mobile cart is the right solution for your institution. Wi-Fi allows any classroom to become a computer lab, as needed, through the use of computer carts equipped with laptops and perhaps a mobile printer. The only wired component for a mobile lab is a wire "drop" for the AP on the mobile cart to be attached. Of course, if the entire campus has been "Wi-Fied," there is no need for the drop.

This kind of wireless solution is reusable and thus allows Wi-Fi to quickly pay for itself.

Provisioning Multimedia

An educational setting typically also means bandwidth-hungry applications such as multimedia presentations. So unlike the other vertical applications discussed in this chapter, most of which have limited bandwidth needs, building a WLAN around 802.11a or 802.11g should be considered when deploying a WLAN in an educational environment. But, of course, the bandwidth capacity offered by 802.11g must be balanced against the fact that it is a new technology. As with any new technology, there are in all likelihood "bugs" that will need to be worked out. However, 802.11g offers a greater reach than 802.11a. In college and university settings where the WLAN will need to extend its reach to dorms as well as providing connectivity around the campus, that is an important consideration when determining which technology to use.

Addressing Wireless Concerns

While wireless campuses offer many benefits, they also pose new challenges for network managers who need to ensure that only authorized users access the network, and that wireless traffic isn't intercepted or tampered with. The management and maintenance of a wireless network infrastructure also presents different challenges than those of a wired infrastructure.

The educational sector's main concerns when it comes to wireless networking include security of personal data, Internet content filtering (for lower-level schools), and interference. Since a school's facilities are often located near businesses and homes, countering interference from other networks may be a challenge.

In many educational environments, it's the student or the facility member who makes the wireless NIC selection, not the school's IT department. Furthermore, there is a growing number of mobile computing devices that are equipped with embedded Wi-Fi capabilities. With a variety of wireless networking equipment to choose from today, an educational institution must educate its user community, in order to create awareness of the type of Wi-Fi network that is deployed in its environment and to avoid confusion.

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COAST-TO-COAST, EDUCATIONAL INSTITUTIONS ARE EMBRACING WI-FI.
  • American University is getting rid of its POTS service and going totally wireless on its 84-acre campus serving 10,000 students.

  • University of Southern Mississippi estimates that it costs $75,000 to wire a building versus $9000 to go wireless. So far this budget conscious university has installed 300 access points.

  • Carnegie Mellon's Wireless Andrew is one of the largest Wi-Fi educational networks. It connects approximately 35 academic buildings, more than 30 campus residence halls, and key outdoor areas.

  • The top (un)wired campuses in the United States include; Carnegie Mellon, Stanford, Georgia Tech, Dartmouth, MIT, Drexel, Indiana University, University of Delaware, University of Virginia, New Jesery Institute of Technology and SUNY Buffalo. (The Wireless Education List Serve has more information. It can be found at www.edu-cause.edu/netatedu/groups/wireless/.)

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The primary reason Wi-Fi is making such inroads into the educational sector is because its most compelling advantages are cross-vendor interoperability and, if designed correctly, practical interference-free communication over reasonable distances. The main disadvantage—security, or the lack thereof—is problematic, but can be overcome.

Admittedly, provisioning security in a multi-vendor environment can be challenging. And although truly manageable and scalable, multi-vendor security solutions are not pervasive today, the industry is working on architectures that will provide security solutions independent of the wireless client adapter and operating system. Until then follow the advice given in Chapter 17.

Wireless Networking Check List

Here is a check list to help you determine your school's wireless networking needs:

  • Do any of the buildings have historic status, asbestos, or any other features that make cabling difficult?

  • How many locations/buildings are to be covered by the wireless network?

  • Are any of the buildings more than one story? If so, is the entire building to be wirelessly enabled?

  • What type of network is currently in place?

  • How many users currently use the network? How many end-users is the network projected to support in one year, three years, five years?

  • Are there any open hubs on the existing network?

  • How does the school currently access the Internet? Does that access method cover the entire school? If not, how is it supplemented (by dial-up service)?

  • Does the school currently have network printers?

  • Have you determined the area the wireless network should cover?

  • Have you performed a site survey?

  • How many laptop computers will be needed? How many will need to be Wi-Fi-enabled?

  • How many desktop computers will be needed? How many will need to be Wi-Fi-enabled?

  • How many wireless network interface cards will be needed? What type?

  • Does the school want to support wireless carts? If so, how many?

  • How many students are expected to use the wireless carts?

  • What percentage of spare parts will you want on hand?

  • Will the end-users require help desk support?

  • Will the IT staff require training on the new technology?

  • Do you require professional assistance with the site survey?

  • Do you require outside assistance with the deployment process?

  • Will you require that specific applications be installed on new computers prior to receiving them?

Whatever the educational environment, be it primary or secondary grades, private or public schools, a wireless LAN solution can enable your institution to deliver technology-based instruction resulting in information on demand. It can free space currently used by computer labs and, at the same time, optimize the time of students using the computers because Wi-Fi enables access to information whenever and wherever the learning takes place.

Case Studies

Howard University

Howard University, a world-renowned university with 91 buildings and four campuses in the Washington, D.C. area, has installed a high-speed voice, data, and video network that serves all of its more than 25,500 students, faculty, and staff, whether they're in a dorm, classroom, library, lab, or roaming the campus.

Students can learn better using new technologies, says Charles Moore, who, at the time was Howard's interim vice provost and CIO. "We're connecting our students with a web of technology that makes it easier for them to achieve their education. It's really become almost a recruiting tool," he says.

Howard installed the $10.4 million network to meet its objective of providing integrated communications to each student. The network made a huge difference in how students view the school and how much more easily they get their work done, according to Pamela Cohen, a Howard graduate with a bachelor of science degree in information systems.

In many respects, Howard is catching up with what other schools offer, Cohen says; most other schools she's familiar with have cable-TV and modem lines in their rooms. But Howard's installation of high-speed Ethernet ports and wireless networking capabilities in students' rooms puts it ahead

The network (wired and wireless) is one of a series of ongoing projects to make advanced computing and networking technology available to Howard's students and faculty. "We've immersed our students and also our faculty in technology," Moore says.

Believing that technology is fundamental to education in the 21st Century, Howard University President H. Patrick Swygert pledged to provide access to the Internet for every student as of the 2000–2001 academic year. This led not only to an extensive, best-of-breed wired network, but also the installation of a pervasive wireless network from Cisco Systems.

The university constructed its network in two stages. As part of the first stage, the university completed construction of a $4.5 million computer "super lab" with 200 computer stations including PCs, iMacs, Sun, and Microsoft workstations (and Dell Computer servers) within Howard's Technology Center. iLab, as it's called, is open around the clock.

The university has three other technical labs on campus, one with a PictureTel Corp. videoconferencing system, one with iMacs equipped with flat-panel cinema-style screens and software for media and graphics projects, and a third with powerful servers and workstations for math and engineering students.

At the same time it built iLab, Howard also constructed two new libraries, each with hundreds of Ethernet ports, wireless LAN access, and extra desktop computers and notebooks for student and faculty use. For example, the $27 million law library has 690 Ethernet ports, and the $27 million health-sciences library has 700 Ethernet ports.

As far as the wireless network is concerned, Howard University's chief information officer, A. Burl Henderson, and his staff researched different options, and chose Cisco's Aironet wireless solution because, according to Henderson, "it was competitive with other products and also due to our long use of Cisco networking equipment." But Henderson also said the Cisco Aironet 340 series of products were chosen because of the features they offered, the ease of installation, and cost-effectiveness they provided, and their ability to integrate with the wired network infrastructure. Installation included Cisco Aironet access points throughout the residence halls, and network interface cards in user computers.

The University began its "Wi-Fiacation" with a pilot project in 2000, in which 3000 students participated. During the pilot program, the school offered free wireless interface cards to the students and promoted the new wireless access within residence halls. The pilot was a resounding success. Network administrators quickly drew up plans to add wireless connectivity to other areas of the campus, including libraries, common areas, and classrooms.

Hundreds of Cisco Aironet 340 series APs were installed, covering a total of 1,993,208 square feet (185,175 square meters) in the hallways of 12 residences. They integrate easily into the University's wired network via a single autosensing RJ-45 port. Each Cisco Aironet 340 series AP acts as a bridge, forwarding at media speed between the Ethernet and wireless protocols. The 250 APs are connected to the campus network via copper wire that is connected to a fiber optic infrastructure in each building.

"We engineered the network so that there would be no more than 20 students per access point," says Henderson.

Students bringing their own PCs to school are offered the loan of Cisco Aironet 340 series network interface cards (NICs), enabling them to receive wireless Internet access within 400 feet of an access point. Each credit card-sized NIC has a radio transmitter/receiver that establishes the connection with the access point, much like cellular telephones.

Students without laptop or notebook computers at Howard can use PCs and Macintoshes at the computing center in each residence hall. Each center is also wireless enabled.

Network administrators at Howard University saw an enormous increase in network activity after the Cisco Aironet wireless LAN was installed. "We routinely have over a thousand simultaneous users on the network at peak use hours," says Henderson. "I believe that this is a clear indication of the success of the implementation. Clearly we expect these numbers to increase, as our faculty become more accustomed to using the Internet as a research and teaching tool."

The popularity of the wireless network with residence hall students quickly caused plans to be drawn up to introduce wireless infrastructure throughout the Howard campus, beginning with dorms, libraries, student lounges, and classrooms. So, during the second stage of its extensive IT overhaul, Howard not only installed an integrated voice, data, and video network, it also completed the installation of 802.11b wireless LANs in all its dorms, so students with notebook computers equipped with 802.11b wireless-access cards can stay connected to the university's network while moving around in their dorms.

In addition to offering wireless LAN access in campus dorms and at the university's computer labs and libraries, Howard envisions building a "wireless canopy" to blanket the entire campus with high-speed wireless access by early summer of 2003, Moore says.

The Siemens Enterprise Networks division of Siemens AG won the bid to supply the equipment for the wired network, installing the network cabling and PBX equipment through its HiPath Professional Services business, which provided project management, integration, and installation, plus ongoing support and maintenance services.

In addition to the cabling, Siemens provided Howard with five 5,200-line Hicom 300H PBXs, which included three Hicom 300H Model 80s and two Hicom 300H Model 30s, as well as "flex shelves" that extend calling features from the PBXs to some of Howard's smaller dorms.

Under Swygert's leadership, "the university has really adapted these technologies, and now there's an expectation that we'll have it and that it'll be operational," Moore says.

With all of the technological resources at faculty and students' disposal, "they have access to any kind of information that there is," says Clint Walker, Howard's interim director of user support services and director of iLab. "When you put all these things together, it gives students a lot of resources that let them complete any sort of assignments that they have."

Simon Fraser University

Located in Burnaby, British Columbia, just outside of Vancouver, Canada, Simon Fraser University serves close to 25,000 students, faculty, and staff. The university also has campuses in downtown Vancouver and in nearby Surrey.

The IT team at Simon Fraser University has been interested in wireless networking since 1994. That was the year that one of the university's IT directors presented a research paper outlining how the school soon would need a new building just to house the computers and computer carrels the students would need in the next decade. Over the years, according to Worth Johnson, the school's co-director of operations and technical support, the school came up with a solution-to enable students to bring their own devices on campus. He added, "We immediately began asking ourselves, 'What are the technologies that are likely to work?'"

The university set about to familiarize its end-users and its technical staff with wireless computing through pilot projects. The first was a proprietary point-to-point wireless system, which was tested in 1991; and throughout the 1990s the IT department experimented with different proprietary systems.

Then in 2001, the university, with the help of a Vernier Networks System, deployed a new pilot WLAN based on the 802.11b standard. Pleased with the overall results, the university extended the network over the summer of 2002, to provide more coverage including access points in the Faculty of Education building, the Applied Sciences building, in study areas, and in other interior and exterior areas on campus. The university's IT staff and Vernier specialists also installed ten access points at the university's downtown campus and another 30 access points at its Surrey campus.

The wireless network, which consists of a combination of Vernier Networks 5000 series and 6000 series Integrated Systems and Access Managers, enables students to bring their own computers on campus, where they can connect easily to the network without worrying about cables or plugs. The university even discovered that it could use the Vernier Networks System for AAA (Authentication, Authorization, and Accounting) on both its wireless and wired networks.

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Figure 15.3: The Vernier Networks System includes a Control Server, which manages access rights for the entire network, and Access Managers that monitor, secure, and control traffic flowing through access points. Graphic Courtesy of Vernier Networks.

The WLAN meets the school administrator's primary requirement—whether a computing device is wired or wireless, an end-user can access the network through a simple sign-on procedure. The Vernier system allows faculty, staff, and students to use the same account and password combination (which each end-user is allowed to individualize) whether they are dialing in, or using the wireless network on campus. When an end-user moves from one location to another, they don't need to change their laptop configuration.

But the university had other requirements as well. Johnson explains, "We also wanted to support different platforms, including various PDAs. We wanted to have a single secure sign-on to authenticate users. We wanted to make sure that whatever human interfaces we provided would work across all devices, so a browser-based interface like Vernier Networks' made the most sense."

The new wireless network, with its secure login and support for roaming, has been well received. "The Faculty of Education loves the wireless network," says Johnson. The department has 35 laptops loaned out for workshops and for use by instructors.

Another user community that has responded enthusiastically to the network has been that of students working in the library with their laptops. "There's an area in the library with little rooms where people can meet to collaborate," Johnson reveals. "Those rooms are booked solid. Some of the best feedback we've received has been from students accessing the wireless network from those rooms. Now they can collaborate online. They're pleased with how well everything works."

Also pleased are the faculty at the university's business school and school of applied sciences, whose departments are located at opposite ends of the campus. These deans provided matching funds for wireless coverage in those areas. Their goal? To provide coverage zones running the length of campus, so that someone could walk from one departmental office to the other and maintain network access. The 2001 WLAN expansion meets this goal. The major traffic corridors on campus are covered by the 802.11b network, making wireless access widely available and thereby encouraging network use.

"They don't have to worry about reconfiguring computers. Everything just works. This lays the groundwork for the use of more computers in the classroom."

An important benefit of the Vernier Networks System has been its ability to provide network access to authenticated users whose devices are either configured for another network or misconfigured entirely. Johnson says, "The Vernier Networks System's adaptive networking technology and support of NAT turns out to be very important for us."

Johnson explains: "One of the inhibitors to introducing technology in the world of teaching is mistrust. Over the years, the faculty was required to use classroom equipment that was sometimes unreliable. It was not unusual for this equipment to be moved from room to room many times, and for its configuration to become inconsistent. Frustrated by their experience with this unreliable equipment, faculty members came to mistrust computers in the classroom altogether. And while they've continued to trust their own computers for research, they are wary of using computers for classroom instruction. One of our objectives is to provide network services that enable faculty to bring their own computers to the classroom, where the network can automatically adapt itself to each computer's configuration. This enables faculty to teach using the computers that they are familiar with and that they trust."

The Vernier Networks System enables faculty to trust their computers again. Johnson gives the example of a faculty member working in his office and calling up a web-site that he wishes to discuss in the classroom. The laptop is plugged into the wired network. It has been assigned a fixed IP address. Because Vernier Networks System supports Network Address Translation (NAT) and translates addresses from one network for another, the professor can unplug the laptop from the office's network port, walk across campus to the classroom, plug in the laptop on a different network, and continue accessing the website in front of the class. The Vernier Networks System translates the addresses between the subnets, and enables the professor to access the material he wants, without having to learn how to reconfigure the laptop for a new subnet. The professor gets to use his or her own laptop, a system with which he or she is already familiar, rather than an unfamiliar classroom system or a low-end system built from spare parts.

The faculty has responded enthusiastically to this new capability. "They can trust the network now," says Johnson. "They don't have to worry about reconfiguring computers. Everything just works. This lays the groundwork for the use of more computers in the classroom."

Once the basic wireless network was in place, the university's IT team began to develop new software that could take advantage of the Vernier Networks System's Layer 3 intelligence to improve the accounting system used for the university's print services. Like many universities, Simon Fraser University provides a central printing service for its students. When a student submits a job to be printed, the university's printing software identifies the job by the system name of the computer the student is using. Now that students bring their own computers to campus, though, the university has no way of ensuring that every computer is uniquely named.

The Vernier Networks System's Layer 3 packet inspection engine can identify the student ID associated with every packet traveling on the network, including packets headed for the printer. "We're looking into the idea of developing software based on the Vernier Networks System that would embed the student's authentication ID in the print job, so that every job would be clearly labeled with the ID of the student who sent it," says Johnson. This solution, which would provide a universal system for tracking print jobs submitted by wired or wireless computers, would not be possible without Vernier Networks' Layer 3 technology.

This software project is just the one of many in the ongoing partnership between Vernier Networks and Simon Fraser University. "Vernier Networks has been very responsive," says Worth Johnson. "They've been a good partner."

Stephen K. Hayt School, Edgewater, Illinois

This school, located near Chicago, wanted to provide students with enhanced learning opportunities wherever they might be on campus, by combining hands-on learning projects with wireless Internet access. The school administrators contacted a local consulting firm, Technocrats Consulting, Inc., that specialized in educational systems, to develop a plan to achieve this vision.

Technocrats worked with school personnel to develop the following goals:

  • Implement mobile computing, so that lessons aren't confined to the classroom.

  • Design a system that lets students face the teacher, not the wall where the network connection is located.

  • Continue to utilize the investment made in Mac and PC computers and software.

To accomplish these goals required a single wireless networking system that could work with Hayt School's existing PCs and Macs. The solution Technocrats devised not only met the school administrator's requirements, but it was also quite cost-effective. The plan called for Proxim, Inc.'s Harmony wireless networking solution, which allows both Macs and PCs to be recognized on one wireless LAN system. With the Harmony system onboard, all of the school's 65 laptops (50 Apple iBooks; 15 Dell Inspiron PCs) can be used simultaneously on the same LAN from anywhere on the campus. Students can access the Internet, the school website, classroom files, lesson plans, and collaborative projects from any machine, anywhere on the school grounds.

The Harmony wireless network is perfect for the Hayt School. It supports 802.11b, it is flexible, it provides investment protection, and it can provide an easy and inexpensive migration path to new wireless standards. It maintains the same configuration and management interface, without disturbing the existing installation.

Deploying a Harmony-based 802.11b WLAN is also easy. The initial call to Technocrats was made on April 27, 2001, and on May 29th, students were logging onto the new wireless LAN from both Mac and Dell PC laptops. (To make sure the learning environment was not disturbed, technicians installed the entire wireless network over the three-day Memorial Day holiday.)

Of course, Technocrats first performed a thorough site survey and mapped exactly where each access point would be placed, the coverage range of each, and its channel designation. Then, all of the access point channels were pre-programmed, and Technocrats pre-customized the solution to ensure that both the PC and Apple iBook notebook computers could run seamlessly over one wireless LAN.

During the 3-day holiday, technicians positioned and installed the 49 Harmony AP (44 in classrooms and five in the auditorium, cafeteria and main office) so that they could provide coverage throughout the school. Because of their range, the 44 classroom APs actually covered 55 rooms. The Harmony system provides seamless roaming, so when an end-user walks across campus with a "logged on" laptop, he or she is not aware of the different channel or signal changes that occur as the computer moves connectivity from one AP to another.

Teachers and students really benefit from their newfound liberty. For example:

  • The 3rd grade classes takes laptops into the cafeteria to take advantage of the larger space and create life-sized drawings of the human form. Then they use a correlating student Internet learning site to identify and label the different internal organs.

  • Students from the 7th grade use their laptops to participate in a Northwestern University Collaborative Project. The project works with individual teachers, school project teams, and multi-school collaborations in school districts throughout Illinois. Students are able to use the resources of participating museums, libraries, and cultural institutions for innovative, web-based learning opportunities.

  • One class created a "Wonderful World" environmental slide show, and saved the file on the server. They were then able to present their work in their classrooms and to other classes in the auditorium.

School administrators are looking toward the future possibilities of their new wireless LAN. They have a formal keyboarding program in the works that will enhance the students' ability to use the laptops to their full advantage. Because any hand-held Windows CE device can be recognized on their LAN, the school is also contemplating how those devices can be used to enhance the curriculum.

According to Linda Smentek, Technology Coordinator for Hayt School, "The new system has enhanced learning tremendously. The laptops integrate technology across the curriculum, and by having such mobility, you can teach in a much more hands-on way, wherever the lesson happens to be. We're excited about the new opportunities—a lot of which I'm sure we haven't even discovered yet."



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Going Wi-Fi. A Practical Guide to Planning and Building an 802.11 Network
Going Wi-Fi: A Practical Guide to Planning and Building an 802.11 Network
ISBN: 1578203015
EAN: 2147483647
Year: 2003
Pages: 273

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