Sunday, March 27, 2005

IEEE 802 Family

IEEE 802 refers to a family of IEEE standards about local area networks and metropolitan area networks. More specifically, the IEEE 802 standards are restricted to networks carrying variable-size packets. (By contrast, in cell-based networks data is transmitted in short, uniformly sized units called cells. Isochronous networks, where data is transmitted as a steady stream of octets, or groups of octets, at regular time intervals, are also out of the scope of this standard.)

The services and protocols specified in IEEE 802 map to the lower two layers (Data Link and Physical) of the seven-layer OSI networking reference model. In fact, IEEE 802 splits the OSI Data Link Layer into two sub-layers named Logical link control (LLC) and Media Access Control, so that the layers can be listed like this:

  • Data link layer
  • LLC Sublayer
  • MAC Sublayer
  • Physical layer

The LLC Sublayer of this architecture can optionally be replaced by an ethernet sub-layer. (Alternatively the ethernet frames may be encapsulated into LLC frames as described by RFC 1042, RFC 1390 and the IEEE 802.1H standard.)

The IEEE 802 family of standards is maintained by the IEEE 802 LAN/MAN Standards Committee (LMSC). The most widely used standards are for the Ethernet family, Token Ring, Wireless LAN, Bridging and Virtual Bridged LANs. An individual Working Group provides the focus for each area.

1 Comments:

At 5:21 AM, Blogger Sara said...

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