澳门跑狗论坛

Ubiquity is a tall order, school district technology directors are finding, as they extend school wireless networks to the farthest reaches of their campuses to provide 鈥渁nytime, anywhere鈥� learning.

鈥淲e鈥檙e getting to the point where people are beginning to depend on wireless devices, just like we depend on wired devices,鈥� says Jim Hirsch, the associate superintendent for academic and technology services for the 33,000-student Plano, Texas, school system, which has a reputation as one of the more technologically sophisticated districts in the country.

For schools that are now relying on laptop computers, wireless access to the Internet and other online resources is essential. Many teachers and students consider wireless technologies one of the best ways for accessing educational resources鈥攁nd they constantly are testing the range and capacity of the wireless hubs that technology officials have located in and around schools.

The availability of wireless technologies is also leading to new and better uses for laptops and other devices, says Darrell D. Walery, the chairman of the , or CoSN, a Washington-based educational technology group.

鈥擱ussell Tate/iStockphoto

Wirless access, for example, allows teachers to do more lesson planning and administrative tasks outside their classrooms in other parts of the bulding, and it gives them the ability to move a laptop around a classroom to take notes on student projects, says Walery. He is the director of technology for the 9,000-student Consolidated High School District No. 230 in Orland Park, Ill., southwest of Chicago.

But the growth in wireless applications presents school technology officials with a range of challenges. For instance, users place ever-greater demands on the capacity of wireless-fidelity, or Wi-Fi, the hubs that send data between a school network and the Internet and the laptops equipped with Wi-Fi network cards.

In addition to e-mail, document files, and simple instructional content, users of wireless networks want to download or upload bandwidth-gobbling video or music files as well as big chunks of data.

Capacity Upgrades

In response to such demand, many districts that were among the first to use wireless technologies are now starting to upgrade the routers and hubs that create the wireless 鈥渉ot spots,鈥� or areas where the wireless network can be accessed, from the 803.11b standard, which moves data at a maximum 11 megabytes per second, to 803.11g, at 56 megabytes per second鈥攐ften making the difference between jerky and smooth motion for a streaming video.

Such an upgrade becomes essential when schools have more than a few laptops operating in the same area, whether because of students鈥� use of classroom laptop sets on carts or as part of a one-to-one laptop program.

Yet even that faster speed is still significantly below the capacity of the typical modern wired network, at 110 megabytes per second, which is a reason why school districts are loath to go entirely wireless, even for brand-new schools.

Another problem is that the part of the radio spectrum used by both the 鈥渂鈥� and 鈥済鈥� versions can be interfered with by cellphones, microwaves, and other devices.

For now, district officials see wireless as an add-on to their wired networks鈥攁 way to provide, or boost, coverage in classrooms and outdoors, such as lunch hangouts and even woods along the back boundary of a campus, where science classes might take laptops for environmental measurements.

However, some technology experts are predicting that the next generation of wireless hubs, called 鈥渋ntelligent access points鈥濃�攏ow far too costly for school budgets鈥攚ill parcel out a slice of bandwidth for each user in the vicinity and allow technology administrators to set priorities based on type of use.

As with up-to-date wired switches today, intelligent access points can reserve bandwidth for voice traffic, or for a teacher鈥檚 presentation of a 鈥渟treaming鈥� video so quality does not suffer if a gaggle of students nearby starts downloading video clips at the same time, says Hirsch, the Plano technology director.

Yet technology officials realize that the capacity of their networks will continue to be tested by increasing demands鈥攁s when, for example, students and teachers use more and more Web services such as YouTube to share and access video content.

Some help may come from experts figuring out better ways to squeeze more video data into less bandwidth for low-bandwith devices such as cellphones, Walery notes. Greater compression will lighten some of the burden, at least on school networks. Still, that advantage may be overwhelmed when many students try to access video clips over the same classroom wireless hubs.

Guest Networks

Another challenge occurs when people bring their own laptops to school buildings and want to hop onto the Internet over the wireless network, just as they can do at an Internet cafe or some coffeehouses. Such potential users include students, teachers, visiting consultants, parents, and others.

Letting outside laptops onto the school network increases the risk of the spread of comptuer viruses and hacker attacks, say district officials and security experts. Such worries have led some districts to bar all outside computing devices from accessing their wireless networks, under a philosophy of protecting the school network first.

On the other hand, some districts are laying out a wireless welcome mat.

鈥淭here鈥檚 nothing more frustrating than when somebody comes in and does professional development, and the outside instructor can鈥檛 get on the Internet,鈥� says David N. Trask, the technology director for the 600-student Vassalboro Community School District in Maine.

The Vassalboro schools have a separate wireless 鈥済uest network,鈥� which is connected to the Internet with no links to the district鈥檚 administrative or instructional systems.

The district鈥檚 open hot spots allow any visitor to connect to the Internet. 鈥淎nybody that wants to bring in a laptop, fine. I don鈥檛 care, because you can鈥檛 access our administrative network,鈥� Trask says.

The separate network is filtered to block access to inappropriate content, he adds.

One other district strategy is to issue a guest identification and password to use the school鈥檚 wireless Internet link.

In Illinois, Walery鈥檚 district in Orland Park allows adult visitors to log in using their e-mail addresses. But it has prohibited students from using their personal laptops at school because of concerns about students hacking into school networks.

鈥淚t鈥檚 really kind of sad,鈥� Walery says. 鈥淪chools are one of the few business places where you have hostile users鈥攏ot all of them, but you have a few.鈥�

Home Connections

Wireless of a different sort may provide a way to help school districts bridge the digital divide that prevents some families from accessing school resources online.

Called 鈥渕unicipal Wi-Fi,鈥� it is being considered in Minneapolis, San Francisco, Philadelphia, and other cities鈥攚here broadband Internet access is cost-prohibitive for many families鈥攁s part of negotiations with telecommunications companies.

Chicago, for example, has many low-income families that schools need to reach, says Sharnall S. Jackson, the chief eLearning officer for the 421,000-student public school system there.

Jackson, a member of a committee that Chicago Mayor Richard M. Daley established to study the potential for municipal Wi-Fi, says the city has issued a request for proposals for a high-speed, low-cost broadband network that would blanket the city, providing free access to the Internet.

鈥淭his would really create for us an opportunity to really communicate with parents,鈥� Jackson says.