Technology Description
EoS represents a marriage of two important technologies, one from the telephony
world, and one from the enterprise data world. This section provides an overview of
the key EoS technical concepts. It assumes that the reader has some familiarity with
Ethernet, either through prior knowledge or from the material in the preceding chapters.
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It, therefore, focuses on SONET, the EoS technology that enables SONET to carry
Ethernet, and the application of EoS technology within multi-service provisioning
platform (MSPP) systems.
SONET Overview
SONET has its roots in voice telephony. In the 1980s, many of the Regional Bell
Operating Companies (RBOCs) began deploying fiber-optic transport systems, mainly
to transport plesiochronous DS-1 signals (1.544Mbps); these DS1s typically carried
64kbps voice channels, either from a customer location to a digital switch or between
digital switches. Because these fiber-optic transport systems were based mainly on
vendor-proprietary technology, the RBOCs commissioned Bellcore (now Telcordia) to
develop a uniform technology for fiber-optic transport. Bellcore dubbed this technology
Synchronous Optical Network (SONET), and introduced it into ANSI committee T1X1
in 1985.
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