scope:

A telecommunication network is a complex network which can be described in a number of different ways depending on the particular purpose of the description. This Recommendation describes the network as a transport network from the viewpoint of the information transfer capability.

This Recommendation provides a set of constructs (definitions and diagrammatic symbols) and the semantics that can be used to describe such a viewpoint.

A transport network transfers user information from a sender at one location to a receiver at another location. A transport network can also transfer various kinds of network control information such as signalling, and operations and maintenance information for the control functional group.

This Recommendation describes the functional architecture of transport networks in a technology-independent way. The generic functional architecture of transport networks provides the basis for a harmonized set of functional architecture Recommendations for specific layer network technologies, including those that use connection-oriented circuit switching (commonly referred to as CO-CS) or connection-oriented packet switching (commonly referred to as CO-PS), and connectionless packet switching (commonly referred to as CL-PS), and a corresponding set of Recommendations for management, performance analysis, and equipment specifications.

This Recommendation provides the definition of the architectural constructs that are required to describe a transport network. The theoretical material that was used as the basis for these definitions is provided in Annex A (concepts), Annex B (properties of systems), and Annex C (properties of communications).