N-GEN Communications Web-based Seminars ©NGCS

Seminar - An Overview of Communications Technologies

Module 5 - SONET, WDM, DWDM and B-ISDN Technologies                                      Slide 76 of 76 _________________                                                                                  __________

Glossary

ADM - ADD/Drop Multiplexer is a device that can extract out of high-bandwidth signal certain specific lower-bandwidth signals and insert lower bandwidth signals..

ATM - Asynchronous Transfer Mode - A very high speed, full-duplex, fixed-length 48 byte cell switching scheme for voice, data and video.

Concatenated STS-1 - is a Synchronous Transport Signal, composed of n STS-1s combined. It is used to transport signals that do not fit into a STS-1 payload. It is used to transport a digital video channel.

DWDM - Dense WDM technology allows more channels packed more closely into the same fiber.

OAMP - Operations, Administration, Maintenance, and Provisioning provides necessary facilities and functions to manage a network.

Payload - An envelope used to transport DS-1, DS-2, DS-3, video, broadband data, ATM and any future services.

SDH - Synchronous Digital Hierarchy is the CCITT-defined world standard of synchronization whose base transmission level is 155 M bps and is equivalent to STS-3 or OC-3 transmission rate.

SONET - Synchronous Optical Network is a standard for optical transport that defines optical carrier levels and their electrically equivalent synchronous transport signals. SONET allows multi-vendor environment and positions the network for transport of new services.

SPE - Synchronous Payload Envelope is a SONET frame structure composed of synchronous transport signal path overhead and payload.

STS-1 - The basic SONET building block signal transmitted at 51.84 M bps data rate. STS-1 frame carries overhead for OAMP surveillance, performance monitoring, and communication channels.

STS-n - Synchronous Transport Signal Level n, is the signal obtained by multiplexing integer multiples of STS-1 signals together.

VT - Virtual Tributary is a signal designed for transport and switching of sub-STS-1 payloads.

WDM - Wavelength Division Multiplexing is a technology used to multiplex signals at many wavelengths into the same fiber. Initially this term was used in industry for multiplexing two wavelengths into one fiber.

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