SONET

SONET (Synchronous Optical Networking) is the American National Standards Institute standard for synchronous data transmission on optical media using lasers or highly coherent light from light-emitting diodes (LEDs). The international equivalent of SONET is synchronous digital hierarchy (SDH). Together, they ensure standards so that digital networks can interconnect internationally and that existing conventional transmission systems can take advantage of optical media through tributary attachments. The method was developed to replace the plesiochronous digital hierarchy (PDH) system for transporting large amounts of telephone calls and data traffic over the same fiber without synchronization problems.

SONET