Functional modelling for target B-ISDN signalling

It is argued that, in order to meet the needs of future broadband ISDN (B-ISDN) telecommunication services and network architectures offering multimedia services, it is necessary to separate call control and bearer connection control in the functional model. The development of such a model, following a three-stage methodology, is described. The functional description (stage 2) is being derived from the service description (stage 1). By separating call and connection control, connections belonging to the same call can be routed through the network independently