What is SONET - Synchronous Optical Network?

The Network of the Office Building
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Sonet is a physical layer network technology designed to carry large volumes of traffic over relatively long distances on  fiber optic cabling. SONET was originally designed by the American National Standards Institute (ANSI) for the USA public telephone network in the mid-1980s.

Sonet Characteristics 

SONET possesses several characteristics that make it appealing on the Internet today:

  • SONET defines clear interoperability standards between different vendors' products
  • SONET can carry nearly any higher-level protocol (including IP), and
  • SONET includes built-in support for ease of management and maintenance.


Generally speaking, SONET performs at very high speeds. At the base signalling level called "STS-1," SONET supports 51.84 Mbps. The next level of SONET signalling, STS-3, supports triple the bandwidth, or 155.52 Mbps. Higher levels of SONET signalling increase the bandwidth in successive multiples of four, up to approximately 40 Gbps!

The speed and cost of SONET make the technology competitive with alternatives like ATM and Gigabit Ethernet.

Also Known As: Synchronous Optical NETwork