What Is SONET Optical Network?

When it comes to data transmission, optical fibers have plenty of advantages to offer when compared to conventional wire cables. Some of the most important ones are:

  • An ability to transmit data over longer distances,
  • Lower rates of data loss,
  • Higher data rates and
  • Less vulnerability to electromagnetic interferences.


The protocols that govern data transmission over optical fiber are known as SONET or Synchronous Optical Networking. Here is taking a look at SONET optical network in some detail.


What is SONET?

SONET is a protocol that has been developed by the American National Standards Institute. It governs synchronous digital transmission on optical media. When one is talking about this protocol in the global domain then it becomes known as SDH or synchronous digital hierarchy.


SONET is characterized by:

  • Providing a standard for line rates
  • Being the basis for BISDN or broadband integrated services digital network
  • Its definition of a base rate of 51.84 megabits per second
  • Its application for different protocols such as Ethernet and TCP/IP traffic too.


Connection rates

SONET is the most widely used transmission technology deployed by large telecom carriers. It is denoted by different connection rates as well. The lowest or most basic rate as mentioned above is STS-1 where STS stands for synchronous transport signal. There are two ways to look at connection rates. On one hand you have the STS and on the other the OC or optical carrier.


Thus, you get connection rates which can be described with different speeds:

  • STS-96 OC-96 has a rate of 4976.64 megabits per second
  • STS-12 OC-12 is at 622.08 megabits per second and
  • STS-1 OC-1 is at 51.84 megabits per second.


Just to put things in a bit of perspective, an STS-1 connection rate is said to be equal to a T3 connection. SONET establishes optical carrier levels up to 9.95 gigabits per second or OC-192.


SONET architecture

When one talks about network architecture, SONET relies on network that has the capability of transmitting data even if a portion of the network has failed. SONET uses the following network architectures:

  • Bidirectional line-switched ring which could be either 2-fiber or 5-fiber variants
  • Unidirectional path-switched ring and
  • Linear automatic protection switching.


Advantages of SONET

SONET is a comprehensive standard which is capable of providing the foundation for global telecom networks well into the future. It has replaced many older telecom systems and protocols thanks to the advantages it offers. Due mainly to its bandwidth availability and flexibility, SONET can deliver benefits such as:

  • Better network reliability
  • Lower equipment investment
  • Better connectivity between different telecom carriers
  • Highly flexible architecture which means that it can carry many applications created in the future too.


Considering the fact that telecom is one sector which sees a lot of rapid growth and progress, it makes sense to invest in something like SONET in order to remain relevant in the future too. It is the implementation of SONET that has made it possible for global telecom carriers to provide an interconnection between their already deployed fiber optic systems and digital carrier systems.