Cutting the Cables

The promise of the "wireless revolution" in networking is certainly tantalizing: Desktop computers connected and communicating freely with one another between floors or even nearby buildings without the use of network cables. Another potential benefit is untethered network access using portable devices to those whose job requires them to be mobile. This includes such diverse professions as doctors, nurses, warehouse employees and stock-exchange traders.

For network managers, the promise of wireless networking is as much about freedom from the tyranny of cables as anything else. Network cabling is expensive to install and maintain. Drawing cable through an entire building can be difficult and costly work, particularly if the building is old and contains toxic construction materials, such as asbestos. Cables can develop bad connections or break. Locating and replacing a broken network cable running through a crowded workplace is not a task network managers look forward to.


How Wireless Works

Like its cabled cousin, wireless takes advantage of the ability of waves in the electromagnetic spectrum -- such as electric waves flowing in a wire, radio waves or light waves -- to carry information from point A to point B. Electric currents flow in wave patterns. Networks -- both wired and wireless -- work by converting information into a form that can be carried by these electronic waves and then reconverting it back to its original form at the receiving end.

Instead of waves flowing through electric cables, wireless technology uses radio or infrared waves to carry network information. Radio and infrared are specific waveforms within the electromagnetic spectrum. Wireless-network hardware translates information into a compatible form that can be laid onto and carried by a radio wave. Other devices decode the wave back into the original information.

Wireless networks generally contain a network adapter and an access point. The network adapter is the electronic interface between the client computer (e.g., a notebook PC) and the wireless network. It performs the same function as a network interface card (NIC) in a wired Ethernet network. The access point is a transmitter/receiver that provides the bridge between the wireless network and a wired network. An access point (which may have an antenna attached) may be mounted anywhere provided the desired coverage is obtained.


Chasing Standards

As with any emerging technology, the development and acceptance of standards are key to large-scale investment by manufacturers and widespread adoption by consumers. The main standard governing wireless networking for local area networks (LANs) is the Institute of Electrical and Electronics Engineers (IEEE) Wireless-LAN specifications, 802.11. The wireless-LAN standard is a subset of a series of IEEE standards covering local and metropolitan area networks. It covers both radio and infrared wireless technology.

The approval in June 1997 of the 802.11 standard has provided wireless vendors an agreed-upon set of specifications against which their products may be developed. This should let manufacturers provide greater interoperability between their products and, in turn, provide consumers greater confidence when investing in wireless-network hardware and related technologies.

According to the Wireless LAN Alliance , the IEEE standard "represents an important milestone in WLAN systems since customers can now have multiple sources for the components of their WLAN systems. As products are introduced compliant to the standard, users can choose from a number of vendors that provide compatible products. This increases competition and provides the potential for lower-cost products."


Bringing Wireless to Education

As it has been during much of the computer revolution, the education sector finds itself as a natural early-adopter for a new technology, in this case, wireless networking. Contributing factors include: school buildings often contain older construction materials making installation of wired networks time-consuming and expensive; wireless solutions can be cheaper to install and provide lower monthly maintenance costs; and a growing local, state and national movement to get schools online. A U.S. Department of Education survey indicated that 50 percent of the nation's public schools have at least one computer with Internet access, but more than 90 percent of instructional classrooms are not yet connected. Funding and inadequate wiring were the most frequently cited barriers to acquiring online access.

One school system that recently opted for a wireless solution is the Pittsylvania County School District in Pittsylvania, Va., which installed a wireless backbone that brings high-bandwidth connectivity to 22 computer labs in 19 schools. This network connects every school office, library, guidance office and main computer lab to the WAN and the Internet, bringing high-speed Internet access to 10,000 children across the county.

"Now we can provide increased bandwidth for the same amount of money [as a system using telephone company lines]," said Rickey Parker, the district's director of information technology. "And since we purchased the equipment instead of paying monthly fees, we eliminated worrying about getting funding every year. Plus, a big advantage is that with my staff of only four technicians, we can do the work ourselves -- saving even more money."

The school district also has an aggressive second phase planned that will upgrade its wireless system to a backbone with a 100Mbps standard. All regions will have 100Mbps off a 45Mbps DS3 instead of regional DS1 ATM links. Information about its wireless network solution is online.


The Future

Time will tell whether WLANs are destined to replace the tried-and-true systems of cabled networks or whether wireless will be forever relegated to a niche role, providing network access to mobile workers and rural organizations that cannot afford cable- or fiber-installation costs. The implementation of industry standards is still in the very early stages. The 802.11 WLAN standard is a first-generation standard. New standards will be needed to address the issues of increased data-transmission rates and higher-frequency bandwidths.

While wireless LAN applications are mostly found in vertical markets, many horizontal applications should come into being as network infrastructures following the new standard are installed. Over time, the increase in demand for 802.11-compliant products should increase competition and make wireless LANs more competitive and economical for virtually all applications requiring wireless connectivity.




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John Stanard is a senior consultant with webworld studios inc., a northern Virginia-based Web application development company. E-mail