In the absence of an industry standard, the early forms of wireless networking were single-vendor
proprietary solutions that could not communicate with wireless network products from other vendors. In
1997, the computer industry developed the IEE 802.11 wireless Ethernet standard. Wireless network
products based on this standard are capable of multivendor interoperability.
The IEEE 802.11 wireless Ethernet standard consists of the IEEE 802.11b standard, the IEEE 802.11a
standard, and the newer IEEE 802.11g standard.
Note: The Bluetooth standard for short-range wireless networking is designed
to complement, rather than rival, IEEE 802.11-based wireless networks.
• IEEE 802.11 was the original standard for wireless networks that was ratified in 1997. It operated at a
maximum speed of 2 Mbps and ensured interoperability been wireless products from various vendors.
However, the standard had a few ambiguities allowed for potential problems with compatibility between
devices. To ensure compatibility, a group of companies formed the Wireless Ethernet Compatibility
Alliance (WECA), which has come to be known as the Wi-Fi Alliance, to ensure that their products
would work together. The term Wi-Fi is now used to refer to any IEEE 802.11 wireless network
products that have passed the Wi-Fi Alliance certification tests.
• IEEE 802.11b, which is also called 11 Mbps Wi-Fi, operates at a maximum speed of 11 Mbps and is
thus slightly faster than 10BASE-T Ethernet. Most IEEE 802.11b hardware is designed to operate at four
speeds, using three different data-encoding methods depending on the speed range. It operates at 11
Mbps using quatenery phase-shift keying/complimentary code keying (QPSK/CCK); at 5.5 Mbps also
using QPSK/CCK; at 2 Mbps using differential quaternary phase-shift keying (DQPSK); and at 1 Mbps
using differential binary phase-shift keying (DBPSK). As distances change and signal strength increases
or decreases, IEEE 802.11b hardware switches to the most suitable data-encoding method.
Wireless networks running IEEE 802.11b hardware use the 2.4 GHz radio frequency band that many
portable phones, wireless speakers, security devices, microwave ovens, and the Bluetooth short-range
networking products use. Although the increasing use of these products is a potential source of
interference, the short range of wireless networks (indoor ranges up to 300 feet and outdoor ranges up to
1,500 feet, varying by product) minimizes the practical risks. Many devices use a spread-spectrum
method of connecting with other products to minimize potential interference.
IEEE 802.11b networks can connect to wired Ethernet networks or be used as independent networks.
• IEEE 802.11a uses the 5 GHz frequency band, which allows for much higher speeds, reaching a
maximum speed of 54 Mbps. The 5 GHz frequency band also helps avoid interference from devices that
cause interference with lower-frequency IEEE 802.11b networks. IEEE 802.11a hardware maintains
relatively high speeds at both short and relatively long distances.
Because IEEE 802.11a uses the 5 GHz frequency band rather than the 2.4 GHz frequency band used by
IEEE 802.11b, standard IEEE 802.11a hardware cannot communicate with 802.11b hardware. A solution
to this compatibility problem is the use of dual-band hardware. Dual-band hardware can work with either
IEEE 802.11a or IEEE 802.11b networks, enabling you to move from an IEEE 802.11b wireless network
at home or at Starbucks to a faster IEEE 802.11a office network.
• IEEE 802.11g is also known as Wireless-G and combines compatibility with IEEE 802.11b with the
speed of IEEE 802.11a at longer distances. This standard was ratified in mid-2003, however, many
network vendors were already selling products based on the draft IEEE 802.11g standard before the final
standard was approved. These early IEEE 802.11g hardware was slower and less compatible than the
specification promises. In some cases, problems with early-release IEEE 802.11g hardware can be
solved through firmware upgrades.