Wireless Home Networking - Index of

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Part I: Wireless Networking Fundamentals
Wi-Fi (802.11a/b/g/n) and Bluetooth are similar in certain respects: They both
enable wireless communication between electronic devices, but they are
more complementary than direct competitors. Wi-Fi technology is most often
used to create a wireless network of personal computers that can be located
anywhere in a home or business. Bluetooth devices usually communicate
with other Bluetooth devices in relatively close proximity.
The easiest way to distinguish Wi-Fi from Bluetooth is to focus on what each
one replaces:
� Wi-Fi is wireless Ethernet: Wi-Fi is a wireless version of the Ethernet
communication protocol and is intended to replace networking cable
that would otherwise be run through walls and ceilings to connect
computers in multiple rooms or even on multiple floors of a building.
� Bluetooth replaces peripheral cables: Bluetooth wireless technology
operates at short distances — usually about 10 meters — and most
often replaces cables that connect peripheral devices such as a printer,
keyboard, mouse, or personal digital assistant (PDA) to your computer.
� Bluetooth replaces IrDA: Bluetooth can also be used to replace another
wireless technology — Infrared Data Association (IrDA) wireless technology
— that’s already found in most laptop computers, PDAs, and even
many printers. Although IR signals are secure and aren’t bothered with
radio frequency (RF) interference, IrDA’s usefulness is hindered by
infrared’s requirement for line-of-sight proximity of devices. Just like the
way your TV’s remote control must be pointed directly at your TV to
work, the infrared ports on two PDAs must be lined up to trade data,
and your laptop has to be “pointing” at the printer to print over the
infrared connection. Because Bluetooth uses radio waves rather than
light waves, line-of-sight proximity isn’t required.
Like Wi-Fi, Bluetooth can offer wireless access to LANs, including Internet
access. Bluetooth devices can potentially access the Public Switched Telephone
Network (PSTN: you know, the phone system) and mobile telephone networks.
Bluetooth is able to thrive alongside Wi-Fi by making possible such innovative
solutions as a hands-free mobile phone headset, print-to-fax, and automatic
PDA, laptop, and cell phone/address book synchronization.
Piconets, Masters, and Slaves
Communication between Bluetooth devices is similar in concept to the ad
hoc mode of Wi-Fi wireless networks (which we describe in Chapter 2). A
Bluetooth device automatically and spontaneously forms informal WPANs,
called piconets, with one to seven other Bluetooth devices that have the
same Bluetooth profile. (A Bluetooth profile is simply a specific Bluetooth