Chapter 9. How
Wireless Connections and WiFI Work
The wired world created a revolution of allowing
people to connect to the Internet. Now the unwired worldthe ability
to connect to the Internet wirelesslyis bringing just as big a
change.
The most popular way of connecting to the
Internet
wirelessly
is via a family of technologies called 802.11
or WiFi. There are several different standards for 802.11, and they
connect at different speeds, including 802.11b standard, which
operates in the 2.4GHz spectrum and transfers data at a maximum
rate of 11Mbps; the 802.11a standard, which operates in the 5GHz
spectrum at 54Mbps; and the 802.11g standard, which operates in the
2.4GHz spectrum and transfers data at a maximum rate of 54Mbps. In
addition, there are other emerging standards that transfer data at
much higher rates, such as the 802.11n, which will transfer data at
rates approximately ten times faster than 802.11g.
To connect to the Internet this way, an 802.11
card needs to be used in a computing device such as a laptop or
palmtop computer, and it needs to connect to a nearby compatible
wireless access point, most often called a router. These routers
can be in a home or business. Increasingly there are also public
access points, called
hot spots
, which allow you to connect
to the Internet from public places such as coffee
shops
, hotels,
and airports.
One problem with WiFi networks is that they can
be vulnerable to snoopers and hackers, who can use a technique
called
war driving
to get into the network.
There are a variety of other ways to connect
wirelessly to the Internet as well, for example by using a
satellite connection.
Satellite-access systems are, in a way, odd
hybrids. Many, but not all, still require that you use a modem. The
modem is used to request information from the Internet, so when you
send information through the Internet, it goes at normal modem
speeds. However, that
requested
information is sent back to you at
the high satellite transmission speeds, not the slower modem
speeds. However, this means that if you're sending email, or
transferring a file to someone via FTP, that information is sent at
modem speeds, not satellite speeds.
When you access the Internet via satellite, you
still use a traditional PC. However, you can also get onto the Web
in other ways using new types of digital devices, most notably
palmtop devices. These little computers, sometimes called personal
digital assistants (PDAs) can literally put the Web in the palm of
your hand. You connect a modem to them and can then get onto the
Internet and send and receive email and browse the Web with them,
although as explained earlier, you can also use them to access the
Internet using WiFi technology.
An emerging technology may be the most
revolutionary wireless technology of allWiMax blankets an entire
metropolitan area with high-speed Internet access, and so wherever
you are, you can be connected to the Internet.
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