Synchronous Optical Network (SONET)
SONET is the North American standard for synchronous digital transmission over optical fibre, closely related to the international SDH standard.
What is Synchronous Optical Network (SONET)?
Its base rate, STS-1, is 51.84 Mbit/s, and higher rates (OC-3, OC-12 and above) are multiples of this. It is now largely replaced by packet-based Ethernet and OTN.