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How To Create a Wireless Network
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Business New Haven
11/12/2001
By: Susan Cornell
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Imagine sitting in your co-worker's office or even on your deck while accessing LAN (local area network) resources such as connection to the Internet, database files, e-mail servers, printers and more. Now imagine not pulling wires through brick walls and across the building to gain access to these LAN services. Wireless LAN technology has hit the mainstream allowing for computer communication without wires to access the local network services.
A wireless LAN is a flexible data communications system implemented as an alternative to or an extension of a wired LAN. Using radio frequency (RF) technology, wireless LANs receive and transmit data over the air, minimizing the need for wired connections. Therefore, wireless LANs combine user mobility with data connectivity.
Wireless LANs have gained strong popularity in a number of markets, including retail, manufacturing, warehousing, health care and academia. These industries have profited from productivity gains of using notebook computers and hand-held terminals to transmit real-time information.
Why wireless? With wireless LANs, network managers can set up or augment networks without moving or installing wires, and users can access shared information without looking for a place to plug in. Wireless offers productivity, convenience and cost advantages over traditional wired networks - plus the ability to connect two buildings if installing a cable is impractical.
Wireless configurations: Wireless LANs can be complex or simple. The most basic would entail two PCs equipped with wireless adapter cards set up on an independent network whenever they are within range of each other, known as a peer-to-peer network. This on-demand network requires no preconfiguration or administration; each “client” has access only to the other client's resources and not to a central server.
To extend the range of an ad hoc network, an “access point” (AP) can be installed, which effectively doubles the range at which the devices can communicate. Since the access point is connected to the wired network, each client has access to both server resources and other clients. While each access point can accommodate many clients (15 to 50), they have a finite range - about 1,000 feet outdoors and 500 feet indoors. Thus, for a very large facility such as a warehouse, it will probably be necessary to install more than one access point.
The last item of wireless LAN equipment to consider is a directional antenna. Let's say you have a wireless LAN in your building and wish to extend it to a building a mile away. One solution could be to install a directional antenna on each building, each antenna targeting the other.
Customer considerations: Customers should be aware of a number of factors when considering wireless LAN systems.
One such consideration is range and coverage. The distance over which RF waves can transmit data is a function of product design and propagation path, especially in indoor environments. The only reliable method of determining proper installation of wireless is to have a site survey conducted.
As with wired LANs, throughput in wireless LANs is set-up and product- dependent. Factors affecting throughput include propagation factors, number of users, the type of wireless LAN system used, and the bottlenecks on the wired portions of the LAN.
Customers should also be aware that wireless LAN systems from different vendors might not be interoperable. And the unlicensed nature of radio-based wireless LANs means that other products that transmit energy in the same frequency spectrum may provide some measure of interference to a wireless LAN system. Several standards exist for wireless systems with the most popular being 802.11b, but with other standards in place (OPENAIR) and on the way (802.11a and 802.11g).
Users need very little new information to use wireless LANs. And wireless LANs simplify many of the configuration and installation issues that plague network managers. Since wireless technology has roots in military applications, security is a design criterion for wireless devices; security provisions are usually built into wireless LANs, making them more secure than most wired ones.
Wireless LAN implementation entails both user costs for wireless LAN adapters, and infrastructure costs for wireless access points. Infrastructure costs depend primarily on the number of access points employed. Generally, the cost of installing and maintaining a wireless LAN is lower than the cost of installing a maintaining a wired LAN, for two reasons: First, because wireless LANs simplify moves, adds and changes, they reduce the indirect costs of administrative overhead and user downtime. Second, a wireless LAN eliminates direct costs such as cabling and the labor associated with installing and maintaining the cabling.
Very little exposure to RF energy is provided to those in the wireless LAN system area because radio waves fade rapidly over distance. Additionally, wireless LANs must meet stringent safety regulations of both the government and the industry. No adverse health affects have been attributed to wireless LANs.
Mobility and flexibility make wireless LANs both attractive alternatives and effective extensions to wired networks. Wireless LANs provide all of the functionality of their wired counterparts without the physical constraints. Besides offering end-user mobility, wireless LANs enable portable networks that allow LANs to move with the knowledge of the workers that use them.
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