SONET (Synchronous Optical Networking) is a standardized protocol for transmitting digital signals over optical fiber cables. It has been a cornerstone of modern telecommunications networks, providing high-speed and reliable data transmission. In this article, we will see. Synchronous optical network (SONET) is a standard for optical telecommunications transport formulated by the Exchange Carriers Standards Association (ECSA) for the American National Standards Institute (ANSI), which sets industry standards in the U. This tutorial provides an overview of SDH/SONET, covering basics, HDLC framing, terminologies, rates, and the SONET STS-1 SDH Frame. In this comprehensive guide, we will explore the.