What is SONET?
SONET is Synchronous Optical NETworking. SONET equipment generally uses one wavelength, or lambda, to carry an OC level (see below), which can be divided into time slots for individual circuits. SONET is generally used at the carrier level to build diverse networks to carry the Internet backbone, point-to-point leased lines, and pretty much anything else with a SONET interface (ATM & frame relay switches, voice switches, digital cross connects, other multiplexers). SONET in Europe and Asia is known as SDH (Synchronous Digital Heirarchy). Asia’s SDH differs from Europe’s in some respects. SONET OC levels: OC1 – 52mb/s OC3 – 155mb/s OC12 – 622mb/s OC48 – 2.5gb/s OC192 – 9.6gb/s OC768 – 40gb/s You can divide OC circuits into what are called STS channels, or tributaries. Generally each OC level has a corresponding STS level, and higher bandwidth optical equipment can carry more than one STS channel, such as a combination of any of the following: VT-1.5 = T-1 (1.44mb/s) VT-2 = 2mb/s OC-1 =
