Basic call state model and IN switching state model for an integrated IN/B-ISDN architecture

This presentation shows results achieved in the EURESCOM Project P506 "Harmonization/Integration of B-ISDN and IN". This project dealt with the support of multimedia services in an integrated IN/B-ISDN architecture. The paper focuses on a two level Basic Call State Model (BCSM) and an enhanced IN Switching State Model (IN-SSM) which are suitable to make visible to IN the separation between call and connection control introduced by B-ISDN signalling. The first level of the BCSM (Edge Control Manager) models the setup and monitoring of the edge-to-edge relationships, while the second (Link Control Manager) represents the connection status. The Call Segment concept developed by IN CSI and CS2 needs also to be enhanced when looking towards an IN/B-ISDN integrated architecture. To this extent Edge Segments and Link Segments, which are part of the proposed IN-SSM, have been defined, together with their states and transitions among them.