OTH – Optical Transport Hierarchy. Signals of optical hierarchy are known as OTM (Optical Transport Module). The simplest option (zero level) assumes no wavelength multiplex. Optical transport modules are denoted as OTM-n.m, where n is the number of channels (operating wavelengths) and m expresses the type of signal. Different basic rates can be multiplied; potential combinations refer to OTM-n.123 (2.5; 10; 40 Gbps).
Hierarchic level |
Transmission rate [Mbps] |
It can transmit STM-N |
OTM-0.1 |
2488.32 |
STM-16 |
OTM-0.2 |
9953.28 |
STM-64 |
OTM-0.3 |
39813.12 |
STM-256 |
An STM is Synchronous Transport Module, a basic transport unit in SDH (Synchronous Digital Hierarchy). N stands for multiplication of the basic unit’s capacity.
Hierarchic level |
Transmission rate [Mbps] |
It can transmit |
OTM-n.1 |
n x 2488.32 |
n x STM-16 |
OTM-n.2 |
n x 9953.28 |
n x STM-64 |
OTM-n.3 |
n x 39813.12 |
n x STM-256 |