Introduction to Telecommunications & LAN/WAN Architecture

Telecommunications: Communications at a distance.

Local Area Network (LAN): High-speed, low-error data network covering a relatively small geographic area (up to a few thousand meters). LANs connect workstations, peripherals, terminals, and other devices in a single building or other geographically limited area. LAN standards specify cabling and signaling at the physical and data link layers of the OSI model. Ethernet, FDDI, and Token Ring are widely used LAN technologies.

Wide Area Network (WAN): Data communications network that serves users across a broad geographic area and often uses transmission devices provided by common carriers. Frame Relay, SMDS, and X.25 are examples of WANs.

 

***Please select a layer from the model for more information.***

The Open System Interconnection model (OSI), an International Organization for Standardization (IOS) standard for worldwide communications that defines a networking framework for implementing protocols across a seven layer model. Control is passed from one layer to the next, starting at the application layer in one station, proceeding to the bottom layer, over the transport medium to the next station and back up the hierarchy.

Most of the functionality in the OSI model exists in all communications systems, although two or three OSI layers may be incorporated into one.

OSI is also referred to as the OSI Reference Model or just the OSI Model.

Additional information can be found at the following sites:

National Telecommunications and Information Administration (NTIA) | Online Glossary | Internetworking Technology Overview | International Electrotechnical Commission (IEC) | Institute for Electrical and Electronic Engineers (IEEE) | CISCO Systems

Last updated: 02/28/02

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Information gathered for this site has been pulled from the above resource links.

OSI Model image created using Adobe Illustrator v9