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A111 Wireless Card Adaptor 41
Chapter 5
Chapter 5 - Glossary
Glossary
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 centerd 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.
IP Address
An IP address is a 32-bit number that identifies each sender or receiver of information
that is sent across the Internet. An IP address has two parts: the identifier of a particular
network on the Internet and an identifier of the particular device (which can be a server
or a workstation) within that network.
ISP (Internet Service Provider)
An organization that provides access to the Internet. Small ISPs provide service via
modem and ISDN while the larger ones also offer private line hookups (T1, fractional
T1, etc.).