The basic unit of transmission

The basic unit of framing in SDH is a STM-1 (Synchronous Transport Module level 1), which operates at 155.52 Mbps.

SONET refers to this basic unit as an STS-3c (synchronous transport signal - 3, concatenated), but its high-level functionality, frame size, and bit-rate are the same as STM-1.SONET offers an additional basic unit of transmission, the STS-1 (synchronous transport signal - 1), operating at 51.84 Mbps - exactly one third of an STM-1/STS-3c. That is, in SONET the associated OC-3 signal will be composed of three STS-1s (or, more recently in packet transport, the OC-3 signal will carry a single concatenated STS-3c.) Some manufacturers also support the SDH equivalent: STM-0.

September 20, 2011

Continue

Featured