Wireless Home Networking - Index of

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Part I: Wireless Networking Fundamentals
� Channel: When you set up your wireless network, you have the option
of selecting a radio channel. All stations and the access point must
broadcast on the same radio channel to communicate. Multiple radio
channels are available for use by wireless networks, and some of the
newer wireless APs use multiple channels to increase the speed of the
network. The number of channels available varies according to the type
of wireless network you’re using and the country in which you install the
wireless network. Wireless stations normally scan all available channels
to look for a signal from an AP. When a station detects an AP signal, the
station negotiates a connection to the AP.
� Encryption key: Because it’s relatively easy for a hacker to determine
a wireless network’s name and the channel on which it’s broadcasting,
every wireless network should be protected by a secret encryption key
unless the network is intended for use by the general public. Only someone
who knows the secret key code can connect to the wireless network.
The most popular wireless network technology, Wi-Fi, comes with two types
of security: Wired Equivalent Privacy (WEP) and Wi-Fi Protected Access (WPA).
WEP uses the RC4 encryption algorithm and a private key phrase or series of
characters to encrypt all data transmitted over the wireless network. For this
type of security to work, all stations must have the private key. Any station
without this key cannot get on the network. WPA, which is now built into all
new Wi-Fi equipment and is a free upgrade on most older Wi-Fi equipment,
is far more secure than WEP, and we recommend that you use it. WPA uses
either Temporal Key Integrity Protocol (TKIP) or Advanced Encryption
System (AES) encryption, which dynamically changes the security key as the
connection is used. We talk about using both types of systems in Chapter 9,
with our primary emphasis on WPA, and we promise we won’t test you on
these acronyms at all!
In the home, you’ll most likely get your access point functionality through a
wireless home router or a wireless Internet gateway. These devices combine
the access point with a router, a wired Ethernet network switch, and (in the
case of the gateway) a broadband modem. Similar devices may even throw in
a print server. This Swiss army knife–like approach is often a real bargain for
use in a wireless home network. A stand-alone access point may be part of
your network when you’re adding a second wireless network to the mix (it
would attach to one of the wired Ethernet ports on your router), or if you
have some kind of fancy wired router in place (this isn’t common, but some
folks who work from home may have a special router supplied by their company
for accessing the corporate network).
We use the term AP throughout this chapter to mean either a stand-alone AP
or the AP built into a wireless home router or gateway.
Wireless networking devices can operate in one of two modes: infrastructure
mode or ad hoc mode. The next two subsections describe the differences
between these two modes.