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WEB PROFORUM TUTORIALS PRINCIPAL SPONSORS
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Synchronous Digital Hierarchy (SDH) |
Definition and Overview
Definition
Synchronous digital hierarchy (SDH) and synchronous optical network (SONET) refer to a group of fiber-optic transmission rates that can transport digital signals with different capacities.
Overview
This tutorial discusses synchronous transmission standards in world public telecommunications networks. It will cover their origins, features, applications, and advantages, as well as their impact on network design and synchronous signal structure.
This tutorial concentrates on the most common form of SDH, that defined by the European Telecommunications Standards Institute (ETSI) for Europe but now used everywhere outside of North America and Japan. The Japanese version of SDH differs only in details that are touched on here but are not significant for the purposes of this tutorial. SONET was defined by the American National Standards Institution (ANSI) and is used in North America. This tutorial refers to SONET where appropriate; a more detailed discussion is available in the International Engineering Consortium's (IEC's) SONET Web ProForum tutorial.
The reader is assumed to be comfortable with the basic concepts of a public telecommunications network, with its separate functions of transmission and switching, and is assumed to be aware of the context for the growth of broadband traffic. No specific prior knowledge is assumed about hardware or software technologies.
This material is based on an article first published in the IEE Electronics & Communication Engineering Journal, June 1994, and the copyright to that article is owned by the (UK) Institution of Electrical Engineers.
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