Wireless network standards are changing faster than any other set of standards
in the network communications market. This phenomenon is the result
of the growing popularity of wireless network communications. For example,
corporate network administrators want to be able to let mobile warriors log
on to the main network (cabled with Ethernet) when they show up at the
office, without having to provide Ethernet equipment hookups for them.
Corporate workers want to be able to amble over to the companys mail
server and pick up their e-mail on their handheld devices. The use of wireless
technology will result in more (and cleverer) applications for this convenient
connection method.
The Institute of Electrical and Electronics Engineers (IEEE) is responsible for
setting the standards for wireless local area networks, and the family of specifications
is contained in the standards known as 802.11. Currently, the 802.11
family contains three sets of standards for you to choose from: 802.11a,
802.11b, and 802.11g.
802.11a
The 802.11a standard is fast, but it often requires more complicated devices
and is sometimes more difficult to configure (depending on the type of hardware
devices you use on your network). Its most often found in large corporate
networks, where it serves its wireless purpose in the midst of wired
Ethernet enterprises. Technically, 802.11a can transmit data at a speed of 54
Mbps (technically means that speed is rarely achieved in the real world). It
uses the 5-GHz band, which is less likely to run into other devices that cause
interference problems.
802.11b
The 802.11b standard is the standard that was originally called Wi-Fi (which
stands for wireless fidelity, but almost nobody who uses the term Wi-Fi
knows that, because Wi-Fi has become a term that means network wireless).
Wi-Fi hardware devices are widely available, and theyre all reasonably
priced. All manufacturers of network devices make Wi-Fi products.
This standard can technically communicate at a speed of 11 Mbps, but I
would be surprised if you achieved that speed consistently. One thing I did
notice, however, is that 802.11b devices tend to maintain their speed (even if
its less than 11 Mbps) better over long distances than do 802.11a devices.
The 802.11b devices operate on the 2.4-GHz band, which is also used by other
radio frequency devices. This could give you a problem with interference. See
the section Detouring around obstructions, later in this chapter, for information
about interference.
You may also see devices that are marked as 802.11b+. This is a slightly
faster version of 802.11b, but Ive read about some problems with compatibility
between the two b standards if you use equipment from different
manufacturers.
To make sure you can purchase Wi-Fi products from multiple manufacturers
that can talk to each other, a group exists to certify compatibility. WECA
(Wireless Ethernet Compatibility Alliance) was formed in 1999 to certify interoperability
of wireless local area network products that are built on the IEEE
802.11b specifications. Look for the Wi-Fi certification logo when you buy
hardware. However, keep in mind that while hardware compatibility ensures
communication, different manufacturers may implement security measures
differently (and thats not covered by Wi-Fi certification).
802.11g
The 802.11g standard is the new kid on the block, and has become the latest
standard for wireless networks. Manufacturers of 802.11g devices advertise
communication rates of 54 Mbps, using the same 2.4-GHz band that 802.11b
uses.
Some 802.11g devices are marked G+B. This means that they automatically
recognize, and communicate with, both 802.11b devices and 802.11g devices.
The term used to describe these devices is dual-band. Dual-band devices provide
a way to expand your existing wireless network without starting all over.
(G+A devices are also available for corporate users.) When a G+B device communicates
with a device using 802.11g, communication is established at the
higher speed possible with 802.11g. However, when a G+B device communicates
with a device using 802.11b, the speed drops to that of 802.11b device.
802.11i
At the time of writing, the 802.11i standard is still in the development and
testing stages. Its Wi-Fi with better security
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