General considerations

The concept and the principles of ISDNs are described in Recommendation I.120. The purpose of this Recommendation is to provide a method for the characterization of telecommunication services (including supplementary services) and a definition of the needed network capabilities in an ISDN, in order to support the identified services.

The main objectives are:

a) to give a common framework and tools to be adopted for service description;

b) to show how, starting from the service definition, it is possible to define protocols and network resources for providing such services;

c) to make reference to those Recommendations which are relevant to the above two points.