A call processing mechanism for point-to-multipoint call control in the centralized access node system

The requirements for the centralized access node system (CANS) is based on the ATM cell concentration capability of on-demand or permanent VC level ATM connections between users and public B-ISDN carrier. In view of the functional reference configuration of the B-ISDN user-to-network interface, S/sub B/ reference point is applied to the user side interface of CANS and T/sub B/ reference point to its network side interface. CANS has the capability for the support of unidirectional/bidirectional point-to-point switched ATM VCCs and undirectional point-to-multipoint switched ATM VCCs. The signaling protocol of CANS is built upon ITU-T Recommendation B-ISDN DSS2, Q.2110, Q.2130 and AAL 5.