IEEE 802

In 1985, the Computer Society of the IEEE started a project, called Project 802, to set standards to enable intercommunication among equipment from a variety of manufacturers.

IEEE 802 is a family of Institute of Electrical and Electronics Engineers (IEEE) standards for local area networks (LAN), personal area network (PAN), and metropolitan area networks (MAN). The IEEE 802 LAN/MAN Standards Committee (LMSC) maintains these standards.

The services and protocols specified in IEEE 802 map to the lower two layers (data link and physical) of the seven-layer Open Systems Interconnection (OSI) networking reference model.

IEEE 802 LAN/MAN  Standards:

IEEE 802.1     Standards for LAN/MAN bridging and management and remote media access control (MAC) bridging

IEEE 802.2     Standards for Logical Link Control (LLC) standards for connectivity

IEEE 802.3     Ethernet Standards for Carrier Sense Multiple Access with Collision Detection (CSMA/CD)

IEEE 802.4     Standards for token passing bus access

IEEE 802.5     Standards for token ring access and for communications between LANs and MANs

IEEE 802.6     Standards for information exchange between systems

IEEE 802.7     Standards for broadband LAN cabling

IEEE 802.8     Fiber-optic connection

IEEE 802.9     Standards for integrated services, like voice and data

IEEE 802.10   Standards for LAN/MAN security implementations

IEEE 802.11  Wireless Networking – "WiFi"

IEEE 802.12   Standards for demand priority access method

IEEE 802.14   Standards for cable television broadband communications

IEEE 802.15.2            Bluetooth and Wi-Fi coexistence mechanism

IEEE 802.15.4            Wireless Sensor/Control Networks – "ZigBee"

IEEE 802.15.6            Wireless Body Area Network[16] (BAN) – (e.g. Bluetooth low energy)

IEEE 802.16   Wireless Networking – "WiMAX"

IEEE 802.24   Standards for Logical Link Control (LLC) standards for connectivity

The relationship of the 802 Standard to the traditional OSI model is

The IEEE has subdivided the data link layer into two sublayers:

- logical link control (LLC) and

- media access control (MAC).

Logical link control (LLC) : 

In IEEE Project 802, flow control, error control, and part of the framing duties are collected into one sublayer called the logical link control. Framing is handled in both the LLC sublayer and the MAC sublayer.

A single LLC protocol can provide interconnectivity between different LANs because it makes the MAC sublayer transparent.

LLC defines a protocol data unit (PDU). The header contains a control field used for flow and error control. The two other header fields define the upper-layer protocol at the source and destination that uses LLC. These fields are called the destination service access point (DSAP) and the source service access point (SSAP).

Media access control (MAC): 

Media access control defines the specific access method for each LAN. For example, it defines CSMA/CD as the media access method for Ethernet LANs and the tokenpassing method for Token Ring and Token Bus LANs.

In contrast to the LLC sublayer, the MAC sublayer contains a number of distinct modules; each defines the access method and the framing format specific to the corresponding LAN protocol.