Academic journal article Library Technology Reports

Chapter 2: Wireless Basics

Academic journal article Library Technology Reports

Chapter 2: Wireless Basics

Article excerpt

Now that I have presented a basic structure of general network concepts, I'll focus on wireless networks. In most respects, wireless networks function exactly like wired networks. They obviously use a different media-the airwaves-and follow slightly different technical protocols behind the scenes.

Although in some ways it seems mysterious that wireless networks could work at all, they rely on technologies that have been common for almost a century, going back to the invention of the wireless telegraph invented by Guglielmo Marconi in 1890. We're not surprised or concerned that an FM radio can pick up dozens of music channels across the airwaves from a distant transmission tower. We take cordless telephones for granted. Wireless networks take advantage of these established technologies to transmit computer data.

These days, I don't categorize wireless networking as a cutting-edge technology. It's been around long enough to become very stable and remarkably inexpensive, and it's gone through many generations of improvement since its debut. Just browse the shelves of your local computer store, and you'll see plenty of wireless products marketed to the non-technical home computer user.

This report favors the term "wireless network" to describe wireless local area networks based on the 802.11 family of protocols. Marketing, technical, and industry publications and Web sites often use Wi-Fi or Wireless Fidelity or WLAN (wireless local area network).

Wireless networking has a place almost anywhere computers are used-the home, small office, as well as large businesses and academic campuses. But wireless networking has really taken off in the home-computing arena. Setting up a wired network is a bit out of reach for most households; not many are willing to crawl under the house and install a wiring system.

As more households have multiple computers, as more of us do some or all of our work from home, the demand has increased, and the market has responded with many reliably functioning products remarkably easy to set up and use. Affordable and easy-to-use wireless equipment makes having a full-fledged network in the home a viable possibility.

Wireless Evolution

Wireless has evolved to the point of being a commodity technology, which means you don't have to worry much about whether or not the equipment will work as advertised. With millions of units sold, most of the kinks have been worked out by now.

This wasn't the case in the early days of wireless networks, when the equipment was very finicky and you had to do a lot of testing and adjusting to end up with a functional wireless network. We're past that now; it's pretty much a plug-and-play world-thank goodness! The equipment is developed to the point that just about anyone can set up a wireless network at home.

One of the most popular consumer devices is the wireless router. Designed to provide a broadband Internet connection for multiple computers in the house (or neighborhood!), a wireless router is hooked up to a DSL or cable modem connection. A wireless router bundles a number of functions into a single device. On one side it must have a cable modem or DSL interface. It functions as a wireless access point, a DHCP server, and it creates a private IP network through a built-in IP router with network address translation (NAT). These devices are ideal for the home or small office but wouldn't be recommended for larger business networks.

802.11 Media Access Rules

Wireless networks follow most of the same media access rules as traditional Ethernet--with one important difference. They share the CSMA rules but operate on a principle of Collision Avoidance instead of Collision Detection. In a wireless environment, dealing with collisions is more complex than with optical or copper media. On a wireless network, there may be some devices out of reach of others, making it impossible to detect collisions. …

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