SONET – Syncronous Optical Network

• The Transmission of multiple digital bit streams syncronously over Optical Fiber using Lasers or LED's.

• Also called SDH – Syncronous Digital Network

• Basic Unit of Transmission is a STM-1 (Syncronous Transport Module, Level 1) which operates at 155.520 Mbps

• SONET is a set of Transport containers that allow transmission of a variety of other protocols like POTS, ATM, Ethernet, etc.