Synchronous Optical Network (SONET) in Computer Networks

SONET is a standardized digital communication protocol that uses a fiber optic medium to transfer huge amounts of data across great distances. Multiple digital data streams are transmitted via optical fiber at the same time utilizing LEDs and laser beams in SONET.

Synchronous optical networking (SONET) and synchronous digital hierarchy (SDH) are established protocols that use lasers or highly coherent light from light-emitting diodes to transport multiple digital bit streams simultaneously across optical fiber (LEDs). Data can also be transmitted over an electrical link at modest transmission rates. The technique was created to replace the plesiochronous digital hierarchy (PDH) system for carrying huge volumes of voice and data traffic over a single cable without synchronization issues.

SONET and SDH were designed to transmit circuit mode communications (e.g., DS1, DS3) from a variety of different sources, but they were principally meant to enable real-time, uncompressed, circuit-switched audio encoded in PCM format. Prior to SONET/SDH, the main challenge was that the synchronization sources of these multiple circuits were all different. This meant that each circuit ran at a little different pace and had a slightly different phase. Within a single framing protocol, SONET/SDH allows for the simultaneous transmission of several distinct circuits of various origins.

Elements of SONET

  • STS Multiplexer − It performs signal multiplexing and transforms an electrical signal into an optical signal.

  • STS Demultiplexer − It performs signal demultiplexing. This device converts an optical signal into an electrical signal.

  • Regenerator − A regenerator is a repeater that takes an optical signal and strengthens it.

  • Add/Drop Multiplexer − This device allows you to combine signals from several sources into a single route or delete a signal.

Why is SONET Used?

SONET is a technology that converts electrical signals into optical signals, allowing them to travel across larger distances.

Layers of SONET

  • Path Layer − The Path Layer is in charge of moving signals from their optical source to their optical destination. Path layer functionalities are provided by STS Mux/Demux.

  • Line Layer − The Line Layer is in charge of signal movement across a physical line. Line layer features are available in STS Mux/Demux and Add/Drop Mux.

  • Section Layer − The Section Layer is in charge of signal flow throughout a physical section. Section layer functions are provided by each network device.

  • Photonic layer − The photonic layer relates to the OSI model's physical layer. The optical fiber channel's physical characteristics (presence of light = 1 and absence of light = 0) are included.

Advantages of Using SONET

  • Data is sent over long distances.
  • Electromagnetic interference is minimal.
  • Data rates are quite high.
  • Provides broad bandwidth.