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How Wireless Networks Work

A wireless network or Wireless Local Area Network (WLAN) serves the same purpose as a wired one — to link a group of computers. Because "wireless" doesn't require costly wiring, the main benefit is that it's generally easier, faster and cheaper to set up.

By comparison, creating a network by pulling wires throughout the walls and ceilings of an office can be labor-intensive and thus expensive. But even when you have a wired network already in place, a wireless network can be a cost-effective way to expand or augment it. In fact, there's really no such thing as a purely wireless network, because most link back to a wired network at some point.

The Basics

Wireless networks operate using radio frequency (RF) technology, a frequency within the electromagnetic spectrum associated with radio wave propagation. When an RF current is supplied to an antenna, an electromagnetic field is created that then is able to propagate through space.

The cornerstone of a wireless network is a device known as an access point (AP). The primary job of an access point is to broadcast a wireless signal that computers can detect and "tune" into. Since wireless networks are usually connected to wired ones, an access point also often serves as a link to the resources available on the a wired network, such as an Internet connection.

In order to connect to an access point and join a wireless network, computers must be equipped with wireless network adapters. These are often built right into the computer, but if not, just about any computer or notebook can be made wireless-capable through the use of an add-on adapter plugged into an empty expansion slot, USB port, or in the case of notebooks, a PC Card slot.

Wireless Technology Standards

Because there are multiple technology standards for wireless networking, it pays to do your homework before buying any equipment. The most common wireless technology standards include the following:

  • 802.11b: The first widely used wireless networking technology, known as 802.11b (more commonly called Wi-Fi), first debuted almost a decade ago, but is still in use.
  • 802.11g: In 2003, a follow-on version called 802.11g appeared offering greater performance (that is, speed and range) and remains today's most common wireless networking technology.
  • 802.11n: Another improved standard called 802.11n is currently under development and is scheduled to be complete in 2009. But even though the 802.11n standard has yet to be finalized, you can still buy products based on the draft 802.11n standard, which you will be able to upgrade later to the final standard.

All of the Wi-Fi variants (802.11b, g and n products) use the same 2.4 GHz radio frequency, and as a result are designed to be compatible with each other, so you can usually use devices based on the different standards within the same wireless network. The catch is that doing so often requires special configuration to accommodate the earlier devices, which in turn can reduce the overall performance of the network. In an ideal scenario you'll want all your wireless devices, the access point and all wireless-capable computers, to be using the same technology standard and to be from the same vendor whenever possible.

RECOMMENDED READING:

802.11 Defined: 802.11 and 802.11x refers to a family of specifications developed by the IEEE for wireless LAN (WLAN) technology. 802.11 specifies an over-the-air interface between a wireless client and a base station or between two wireless clients. The IEEE accepted the specification in 1997. See this page for a complete overview of the 802.11x family of specifications.

Wireless Speed & Range

When you buy a piece of wireless network hardware, it will often quote performance figures (i.e., how fast it can transmit data) based on the type of wireless networking standard it uses, plus any added technological enhancements.  In truth, these performance figures are almost always wildly optimistic.

While the official speeds of 802.11b, 802.11g, and 802.11n networks are 11, 54, and 270 megabits per second (Mbps) respectively, these figures represent a scenario that.s simply not attainable in the real world. As a general rule, you should assume that in a best-case scenario you.ll get roughly one-third of the advertised performance.

It's also worth noting that a wireless network is by definition a shared network, so the more computers you have connected to a wireless access point the less data each will be able to send and receive. Just as a wireless network's speed can vary greatly, so too can the range. For example, 802.11b and g officially work over a distance of up to 328 feet indoors or 1,312 feet outdoors, but the key term there is "up to". Chances are you won't see anywhere close to those numbers.

As you might expect, the closer you are to an access point, the stronger the signal and the faster the connection speed. The range and speed you get out of wireless network will also depend on the kind of environment in which it operates. And that brings us to the subject of interference.

Wireless Interference

Interference is an issue with any form of radio communication, and a wireless network is no exception. The potential for interference is especially great indoors, where different types of building materials (concrete, wood, drywall, metal, glass and so on) can absorb or reflect radio waves, affecting the strength and consistency of a wireless network's signal. Similarly, devices like microwave ovens and some cordless phones can cause interference because they operate in the same 2.4 frequency range as 802.11b/g/n networks. You can't avoid interference entirely, but in most cases it's not significant enough to affect the usability of the network. When it does, you can usually minimize the interference by relocating wireless networking hardware or using specialized antennas.

RECOMMENDED READING:
Minimizing 802.11 Interference Issues on Wi-Fi Planet.

Data Security on Wireless Networks

In the same way that all you need to pick up a local radio station is a radio, all anyone needs to detect a wireless network within nearby range is a wireless-equipped computer. There's no way to selectively hide the presence of your network from strangers, but you can prevent unauthorized people from connecting to it, and you can protect the data traveling across the network from prying eyes. By turning on a wireless network's encryption feature, you can scramble the data and control access to the network.

Wireless network hardware supports several standard encryption schemes, but the most common are Wired Equivalent Privacy (WEP), Wi-Fi Protected Access (WPA), and Wi-Fi Protected Access 2 (WPA2). WEP is the oldest and least secure method and should be avoided. WPA and WPA2 are good choices, but provide better protection when you use longer and more complex passwords (all devices on a wireless network must use the same kind of encryption and be configured with the same password).

Unless you intend to provide public access to your wireless network — and put your business data or your own personal data at risk — you should consider encryption mandatory.

DID YOU KNOW...

ad-hoc mode is an 802.11 networking framework in which devices or stations communicate directly with each other, without the use of an access point (AP). Ad-hoc mode is also referred to as peer-to-peer mode or an Independent Basic Service Set (IBSS). Ad-hoc mode is useful for establishing a network where wireless infrastructure does not exist or where services are not required.


Adapted article courtesy of SmallBusinessComputing.com.
You can read the full version here.
Last updated: April 16, 2010

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