Optical Transport Network

ITU-T defines an Optical Transport Network (OTN) as a set of Optical Network Elements (ONE) connected by optical fiber links, able to provide functionality of transport, multiplexing, switching, management, supervision and survivability of optical channels carrying client signals. An ONE may Re-time, Re-Amplify, Re-shape (3R) but it does not have to be 3R— it can be purely photonic.

Standards

OTN was designed to provide support for optical networking using wavelength-division multiplexing (WDM) unlike its predecessor SONET/SDH.

ITU-T Recommendation G.709 is commonly called Optical Transport Network (OTN) (also called digital wrapper technology or optical channel wrapper). As of December 2009 OTN has standardized the following line rates.

The OTUk (k=1/2/2e/3/3e2/4) is an information structure into which another information structure called ODUk (k=1/2/2e/3/3e2/4) is mapped. The ODUk signal is the server layer signal for client signals. The following ODUk information structures are defined in ITU-T Recommendation G.709

Transport network

A transport network, or transportation network is a realisation of a spatial network, describing a structure which permits either vehicular movement or flow of some commodity. Examples are network of roads and streets, railways, pipes, aqueducts, and power lines. One can distinguish land, sea and air transportation networks.

Methods

Transport network analysis is used to determine the flow of vehicles (or people) through a transport network, typically using mathematical graph theory. It may combine different modes of transport, for example, walking and car, to model multi-modal journeys. Transport network analysis is within the field of transport engineering.

References

See also