ABSTRACT: This first Special Report in the Telcordia Notes on . . . series introduces the Synchronous Optical Network (SONET), which is the U.S. (ANSI) standard for optical communications transport. Telcordia engineers have teamed to develop an overview of this complex technology, and the text is based on the latest information available from Telcordia and ITU-T standards organizations.

This report will be of interest to both technical and nontechnical audiences. Engineering and planning groups may wish to concentrate on SONET's timing characteristics, operations capabilities, etc. Nontechnical readers might wish to focus on the basics and the descriptive material written in layman's terms.

SECTION 2 introduces SONET and fiber optics in general. It discusses the basic fiber optics system and the origin of SONET.

SECTION 3 gives the basics of SONET, including the parts of a simple SONET network; SONET frames; the SONET Path, Line, and Section layers; higher-rate frames, the VT1.5 Path, and the relationship between SONET and SDH.

SECTION 4 covers the basis SONET Network Elements, such as the Add/Drop Multiplexer Terminal and Add/Drop configurations, Digital Cross-Connect Systems, the SONET regenerator, Optical Fiber Amplifiers, and digital switches with SONET interfaces.

SECTION 5 introduces SONET rings and gives background on basic Automatic Protection Switching.

SECTION 6 presents SONET transport systems and discusses interoffice networks, loop access network for enterprises and PSTN, and looks at SONET in long-haul applications.

SECTION 7 details synchronization and the Primary Reference Source, covers the stratum clock levels, timing loops, the Building Integrated Timing Supply, and synchronization status messaging.

SECTION 8 covers operations and network management for SONET. It discusses the Operations Communications Network (OCN) and looks at management interfaces.

SECTION 9 discusses practical applications of the technology such as circuit-oriented network applications, ATM over SONET, Hybrid SONET/ATM, SONET/SDH Gateway, Video on SONET, and IP over SONET.

SECTION 10 covers the evolution of SONET and Technology and market trends.