66
ASUS WLAN Card
Chapter 5
Chapter 5 - Glossary
Glossary
Compared with 802.11g: 802.11a is a standard for access points and radio
NICs that is ahead of 802.11g in the market by about six months. 802.11a
operates in the 5GHz frequency band with twelve separate non-overlapping
channels. As a result, you can have up to twelve access points set to different
channels in the same area without them interfering with each other. This makes
access point channel assignment much easier and significantly increases the
throughput the wireless LAN can deliver within a given area. In addition, RF
interference is much less likely because of the less-crowded 5 GHz band.
IEEE 802.11b (11Mbits/sec)
In 1997, the Institute of Electrical and Electronics Engineers (IEEE) adopted
the 802.11 standard for wireless devices operating in the 2.4 GHz frequency
band. This standard includes provisions for three radio technologies: direct
sequence spread spectrum, frequency hopping spread spectrum, and infrared.
Devices that comply with the 802.11 standard operate at a data rate of either 1
or 2 Mbps.
In 1999, the IEEE created the 802.11b standard. 802.11b is essentially identical
to the 802.11 standard except 802.11b provides for data rates of up to 11 Mbps
for direct sequence spread spectrum devices. Under 802.11b, direct sequence
devices can operate at 11 Mbps, 5.5 Mbps, 2 Mbps, or 1 Mbps. This provides
interoperability with existing 802.11 direct sequence devices that operate only
at 2 Mbps.
Direct sequence spread spectrum devices spread a radio signal over a range of
frequencies. The IEEE 802.11b specification allocates the 2.4 GHz frequency
band into 14 overlapping operating Channels. Each Channel corresponds to a
different set of frequencies.
IEEE 802.11g
802.11g is a new extension to 802.11b (used in majority of wireless LANs
today) that broadens 802.11b's data rates to 54 Mbps within the 2.4 GHz band
using OFDM (orthogonal frequency division multiplexing) technology. 802.11g
allows backward compatibility with 802.11b devices but only at 11 Mbps or
lower, depending on the range and presence of obstructions.
Infrastructure
A wireless network centered about an access point. In this environment, the
access point not only provides communication with the wired network but also
mediates wireless network traffic in the immediate neighborhood.
IP (Internet Protocol)
The TCP/IP standard protocol that defines the IP datagram as the unit of
information passed across an Internet and provides the basis for connectionless
packet delivery service. IP includes the ICMP control and error message protocol
as an integral part. It provides the functional equivalent of ISO OSI Network
Services.
