Note: Many topics at this site are reduced versions of the text in "The Encyclopedia of Networking and Telecommunications." Search results will not be as extensive as a search of the book's CD-ROM.

SONET is a standard that defines telecommunication transmissions over fiber-optic cables. It defines the access methods, framing, and other parameters for transporting digital information over an optical communication system. SONET was first proposed by Bellcore (now Telcordia) in the mid-1980s, and then standardized by the ANSI (American National Standards Institute). The ITU adapted SONET to create SDH (Synchronous Digital Hierarchy), a worldwide telecommunication standard. SONET is a subset of SDH that is used in North America. SONET technology issues are managed by NSIF (Network and Services Integration Forum).

SONET was designed as a means to deploy a global telecommunication system, and so SONET/SDH is widely deployed by the world carriers. It uses standardized rates to ensure that telecommunication companies around the globe can interconnect their systems with little trouble. SONET removes the boundaries between the telephone companies of the world. But SONET is not limited to carrier networks. SONET may run directly to large enterprises in metropolitan areas or be used to build campus networks.

This topic continues in "The Encyclopedia of Networking and Telecommunications" with a discussion of the following:

• SONET features
• Fully redundant networks and APS (automatic protection switching)
• Large-scale SONET networks with multiple rings
• ADMs (add/drop multiplexers)
• SONET digital hierarchy
• SONET layered architecture
• ATM and SONET
• PoS (Packet over SONET)
• SONET versus newer optical mesh networks
• DWDM and SONET

See "Network Core Technologies" and "Optical Networks" for a continuation of this topic. Also see "NPN (New Public Network)."

Copyright (c) 2001 Tom Sheldon and Big Sur Multimedia.
All rights reserved under Pan American and International copyright conventions.