SONET, or "Synchronous Optical Network" is a standard for optical telecommunications transport formulated by the Exchange Carriers Standards Association (ECSA) for the American National Standards Institute (ANSI) in the mid-eighties, originally for use in the American public telephone network, following the breakup of AT&T. The international equivalent of SONET is called SDH, for "Synchronous Digital Hierarchy."
SONET, or Synchronous Optical Network is a standard for optical telecommunications
transport formulated by the Exchange Carriers Standards Association (ECSA) for the American National Standards Institute (ANSI) in the mid-eighties, originally for use in the American public telephone network, following the breakup of AT&T. The international equivalent of SONET is called SDH, for "Synchronous Digital Hierarchy."
The need for SONET arose out of the breakup of AT&T, which left a large number of regional (and smaller) telephony carriers managing their own networks independently, creating two large problems. The first was a lack of standardization hampering communications between the various independent networks, and the other was that the standards that did exist made long distance networks prohibitively expensive for the smaller carriers to operate and extend. SONET was created to overcome these challenges.
Still in widespread use today, the largest defined standard SONET signal (STS-768/OC-768) allows for a bandwidth of 29,813.12 megabits per second, with "short" fiber runs being defined as up to around 2 kilometers ( a little over 1 mile), and long runs spanning over 100 kilometers in distance.
A reasonably comprehensive primer on the technical aspects of SONET can be located here, (download via .pdf link), and as usual, Wikipedia has a page with general information and background on the subject as well.
