Call party handling aspects evolution from IN CS-2 to IN CS-3

The call party handling (CPH) approach was introduced in the ITU-T recommendations for intelligent network (IN) Capability Set 2 (CS-2) to cater for services where one party can participate in several calls. These services: call wait, call forwarding, call transfer, three-way calling, usually involve more than two parties i.e. require instantiation of multiple basic call managers (BCM) for one party, and the CPH's role is to facilitate IN control of those multiple instances. Since the CPH acts only under IN control, the entity implementing CPH, IN-SSM, resides entirely in the SSF. IN support for B-ISDN is planned for IN CS-3 and IN CS-4. We propose an enhanced CPH structure to model B-ISDN calls. A call/connection separation model is proposed in order to allow the non-exhaustive following list of operations: (i) add and drop parties within a multiparty call, (ii) add and drop parties within a point to multipoint connection, (iii) add, modify and drop bearer connections within a multiconnection call, (iv) call establishment without connection, (v) connection establishment by another party within a call (third party connection setup), (vi) initiate connection attempt.