Hardware Reference
In-Depth Information
Wireless Fidelity (Wi-Fi) is a logo and term given to any IEEE 802.11 wireless network
product certified to conform to specific interoperability standards. Wi-Fi certification
comes from the Wi-Fi Alliance, a nonprofit international trade organization that tests
802.11-based wireless equipment to ensure it meets the Wi-Fi standard. To carry the Wi-
Fi logo, an 802.11 networking product must pass specific compatibility and performance
tests, which ensure that the product will work with all other manufacturers' Wi-Fi equip-
ment on the market. This certification arose from the fact that certain ambiguities in the
802.11standardsallowedforpotentialproblemswithinteroperabilitybetweendevices.By
purchasing only devices bearing the Wi-Fi logo, you ensure that they will work together
and not fall into loopholes in the standards.
Note
The Bluetooth standard for short-range wireless networking, covered later in this chapter, is
designed to complement, rather than rival, IEEE 802.11-based wireless networks.
The widespread popularity of IEEE 802.11-based wireless networks has led to the aban-
donment of other types of wireless networking such as the now-defunct HomeRF.
Note
Although products that are certified and bear the Wi-Fi logo for a particular standard are
designed and tested to work together, many vendors of wireless networking equipment cre-
ated devices that also featured proprietary “speed booster” technologies to raise the speed
of the wireless network even further. This was especially common in early 802.11g devices,
while newer devices conform more strictly to the official standards. Although these propri-
etary solutions can work, beware that most, if not all, of these vendor-specific solutions are
not interoperable with devices from other vendors. When different vendor-specific devices
are mixed on a single network, they use the slower common standard to communicate with
each other.
Wi-Fi
When the first 802.11b wireless networking products appeared, compatibility problems
existed due to certain aspects of the 802.11 standards being ambiguous or leaving loop-
holes. A group of companies formed an alliance designed to ensure that their products
would work together, thus eliminating any ambiguities or loopholes in the standards. This
wasoriginallyknownastheWirelessEthernetCompatibilityAlliance(WECA)butisnow
knownsimplyastheWi-FiAlliance (
www.wi-fi.org
).Inthepast,theterm
Wi-Fi
hasbeen
usedasasynonymforIEEE802.11bhardware.However,becausetheWi-FiAlliancenow
certifiesothertypesof802.11wirelessnetworks,theterm
Wi-Fi
shouldalwaysbeaccom-
panied bythe boththe standards supported (that is802.11a/b/g/n)aswell asthe supported
