Overview of IEEE and the 802 Committee
The IEEE, founded in 1884,
is a nonprofit professional organization comprised of over 377,000 members
worldwide. The IEEE consists of many individual societies and working groups.
It plays a critical role in developing standards, publishing technical works,
sponsoring conferences, and providing accreditation in the area of electrical
and electronics technology. In the area of networking, the IEEE has produced
many widely used standards such as the 802.x group of local area network (LAN)
and metropolitan area network (MAN) standards, which are listed in Figure
.
The IEEE
802 LAN/MAN Standards Committee (LMSC) develops local area network (LAN) and
metropolitan area network (MAN) standards primarily for the lowest two layers
of the Open Systems Interconnection (OSI) reference model. LMSC, or IEEE
Project 802, coordinates with other national and international standards
groups. Some standards initiated here are published by the ISO as international
standards.
Figure
shows
the architecture defined by the 802 committee and how many different media
access methods are supported with this model. The media access control (MAC)
and the physical layers (PHY) are organized into a separate set of standards
from the logical link control (LLC). This is because of interdependence between
medium access control, medium, and the topology of each standard. At the same
time, a single LLC process can support the logical functions for all underlying
MAC and PHY protocols.
As shown in Figure
, the combination
of the 802.2 LLC standard and any given MAC protocol is functionally equivalent
to the OSI data link layer. The MAC and LLC processes are typically referred to
as sublayers of the data link layer.
IEEE 802.11
The term 802.11 actually refers to a family of
protocols, including the original specification, 802.11, 802.11b, 802.11a,
802.11g and others, as shown in Figure
. The 802.11 is a
wireless standard which specifies connectivity for fixed, portable, and moving
stations within a local area. The purpose of the standard is to provide
wireless connectivity to automate machinery and equipment or stations that
require rapid deployment. These may be portable, handheld, or mounted on moving
vehicles within a local area.
The 802.11 standard is officially called
the IEEE Standard for WLAN MAC and PHY specifications. It defines the over the
air protocols necessary to support wireless networking in a local area. The
primary service of the 802.11 standard is to deliver MAC Service Data Units
(MSDUs) between peer LLC devices at the data link layer. Typically, a radio
card, or NIC, and one or more access points provide the functions of the 802.11
standard.
The MAC and PHY characteristics for wireless local area
networks (WLANs) are specified in the 802.11x standard. The MAC layer in this
standard is designed to be able to support additional physical layer units as
they are adopted, dependent on the availability of spectrum and new modulation
techniques.