What is SONET?

SONET stands for Synchronous Optical Networking. It is a protocol for transmitting a huge volume of data over long distances using a fiber optic medium. Synchronous Optical Networking was primarily developed in 1984 and then standardized by the American National Standards Institute (ANSI) in 1988.

Using Synchronous Optical Networking, multiple digital data streams are transferred at the same time over optical fiber using the laser beam and LEDs. The hardware related to Synchronous Optical Networking was manufactured to provide better configuration and reliable services to its users. It may use a re-generator for long haul distances and also boosts signals weak signal that has already travelled for a long distance.

SONET supports various streams at the same time and provides efficient services in telecommunication systems. It uses standardized line rates, therefore all kinds of organizations can be interconnected using SONET. The network architecture of a SONET relies on transmitting data even if a portion of the network has failed. SONET uses bidirectional line-switched ring which could be either 2-fiber or 5-fiber variants, unidirectional path-switched ring and Linear automatic protection switching.

SONET Connection Data Rates

SONET defines interface standards at the physical layer of the OSI model. It establishes Optical Carrier (OC) levels from 51.8 Mbps (OC-1) to 159252.48 Mbps (OC-3072). The figure below illustrates the different line rates of Optical Carrier (OC).

Advantages and Disadvantage of SONET

Synchronous Optical Networking is the base for global telecommunication networks due to comprehensive standards. Bandwidth availability and flexibility is the main advantage of Synchronous Optical Networking. So let’s see the advantages and disadvantages of Synchronous Optical Networking.


  • Better network reliability
  • Lower equipment cost
  • Synchronous Optical Networking offers network survivability features
  • Provide Better connectivity between different telecom carriers
  • Synchronous Optical Networking has a highly flexible architecture, therefore It is compatible with legacy and future network
  • Very high efficiency
  • Allows transportation of all  forms of traffic
  • Standard optical interference
  • Easy Multiplexing and De-multiplexing is easy
  • Remote operation capabilities
  • Synchronous Optical Networking provides fast restoral and protection
  • Out of band management system


  • Synchronous Optical Networking has no interoperable standard
  • Tributary services require Synchronous Optical Networking mux services
  • Synchronous Optical Networking management system not well equipped to handle the DWDM system
  • Bandwidth efficiency is a problem at a higher capacity
  • More overhead is required