Wi-Fi Basics: A Beginner's Guide to the Wireless Web

Posted 10/18/2011 at 2:42pm | by Tim Ferrill

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Mind your Bs, Ns, and Gs as we break down the ABCs (and many Ws) of Wi-Fi

The popularity of home networks has increased dramatically over the last decade, a phenomenon which can be directly attributed to the increase in broadband availability, but credit is also due to the accessibility that Wi-Fi provides to consumers. Not only are Wi-Fi products easy to configure and relatively inexpensive to implement, but many home computing devices have wireless radios pre-installed.

While connecting to a wireless network can be as simple as a few button presses or taps, there is a lot that goes into making the bits magically travel through the ether. We’re going to take a look at some of the building blocks that go into making your wireless network stable and fast, with an eye toward security and standards. We’ll also cover some of the devices that can improve your wireless network and ways you can use your Wi-Fi while away from home.

Important Terms

In order to have an intelligent conversation about Wi-Fi, there are a couple of key terms that need to be defined up front. The first is the SSID (Service Set Identifier) or network name. The SSID is the door to connecting to a Wi-Fi network, and is often the only piece of information you will need to get connected.

More of a concept than a term is the idea of channels. Like any Radio Frequency based technology, Wi-Fi uses radio waves of different band-widths to transmit data. Channels define the range of wave-lengths that a transmitter uses. For example several of the Wi-Fi standards use the 2.4GHz frequency, which ranges from 2.4000-2.4835GHz. This frequency range is divided into 13 channels which includes substantial overlap. To make matters more confusing only certain channels are usable from a legal standpoint in different countries. The United States for example uses channels 1-11.

802.11 Standards

The term Wi-Fi refers specifically to the IEEE 802.11 set of standards for wireless networks. Different individual standards are designated by a letter following the 802.11, such as in 802.11g or 802.11n. In general all of the 802.11 standards operate on either a 2.4GHz or 5GHz radio frequency, though some can work on both bands.

802.11a and 802.11b are some of the oldest the Wi-Fi standards and operate on the 5GHz and 2.4GHz frequencies respectively. It could be said that 802.11b was the standard that popularized Wi-Fi, and many legacy devices still utilize this standard today. The biggest differentiators between these original standards from a practical standpoint are speed and range. 802.11a enables speeds of up to 54Mbit/s but the shorter wavelength isn’t as effective at penetrating walls and other obstructions making it less feasible for home networks. 802.11b is limited to 11Mbit/s of throughput, but the 2.4GHz frequency handles signal degradation better.

802.11g combined the benefits of its predecessors, offering 54Mbit/s using a 2.4GHz radio. An additional benefit of using 802.11g is the backward compatibility with 802.11b client devices, though using an 802.11b device on an 802.11g network will reduce the data rate for all clients to 11Mbit/s.

802.11n is the current Wi-Fi standard, and supports the use of both 2.4GHz and 5GHz bands. This ability to use both sets of frequencies is known as MIMO (Multiple-Input Multiple-Output). The key benefits to using 802.11n devices are data rates up to 600MBit/s, and some additional security features. 802.11n offers backward compatibility, though for performance reasons these features are optional, and are not always enabled.

Device Types

Much of the confusion with Wi-Fi is due to the number of devices on the market and the range of terms that are used to describe hardware that perform the same functions. The simplest way to look at a wireless network is to realize that there are essentially only two types of devices, Access Points and Clients, both of which can come in a variety of form factors.

An Access Point is generally the core of your wireless network and is generally physically connected to a wired network as well. Configuration of your wireless settings such as the radio channel, security, and SSID is managed on the Access Point itself. Some examples of Access Point type devices are Wireless Routers or Wireless Range Extenders. While the differences between these monikers are subtle, they can be important to how your network is configured. In its purest form, an Access Point is simply a device that connects a wireless network to a wired network. A Wireless Router indicates that the device includes additional functionality from a networking standpoint that will allow various devices to talk to each other and share an internet connection. Range Extenders are a little hard to explain, but essentially combine features of both Access Point and Client to extend the range of your wireless network without requiring you to run additional networking cable.

Wi-Fi Client devices are any device that connects to the wireless network offered up by an Access Point. These could be laptop or desktop computers, tablets, cellular phones, printers, or even home theater equipment. Typically a Wi-Fi client will have some means of connecting to a specific SSID or list of SSID’s, and the ability to configure security settings like an encryption key or passphrase. Clients can also create an ad-hoc or peer-to-peer network, which is made by two clients connecting to each other. This doesn’t offer the same flexibility or power of an Access Point based network, but there are scenarios where a peer-to-peer network makes sense.