What is SONET & SDH?
SONET and SDH are a set of related standards for synchronous data transmission over fiber optic networks. SONET stands for Synchronous Optical Network and SDH is short for Synchronous Digital Hierarchy. SONET is the United States version of the standard published by the American National Standards Institutue (ANSI). SDH is the international version of the standard published by the International Telecommunications Union (ITU).
Speed
OC stands for Optical Carrier
STS stands for Synchronous Transport Signal
Optical Level |
Electrical Level | Line Rate (Mbps) |
Payload Rate (Mbps) |
Overhead (Mbps) |
SDH Equivalent |
OC-1 |
STS-1 | 51.84 | 50.112 | 1.728 | – |
OC-3 | STS-3 | 155.52 | 150.336 | 5.184 | STM-1 |
OC-12 | STS-12 | 622.08 | 601.344 | 20.736 | STM-4 |
OC-48 | STS-48 | 2488.32 | 2405.376 | 82.944 | STM-16 |
OC-192 | STS-192 | 9953.28 | 9621.504 | 331.776 | STM-64 |
OC-768 | STS-768 | 39813.12 | 38486.016 | 1327.104 | STM-256 |
What is Clear Channel or channelized?
Clear channel means the entire payload rate is available as a single channel of communications or flow of packet or cell.
The opposite of clear channel is "channelized". In a channelized link the payload rate is subdivided into multiple fixed rate channels.