Summary

This Supplementary Service describes the procedures and the signalling protocol for the Call Intrusion supplementary service in H.323 (Packet Based Multimedia Communications Systems) networks.

The Call Intrusion supplementary service (SS-CI) enables a calling user A, encountering a busy destination user B, to establish communication with user B by breaking into an established call between user B and a third user C.

This Recommendation makes use of the "Generic functional protocol for the support of supplementary services in H.323" as defined in ITU-T H.450.1.

This Recommendation requires H.323 version 2 (1998) or later. Version 2 products can be identified by H.225.0 messages containing a protocolIdentifier= {itu-t (0) recommendation (0) h (8) 2250 version (0) 2} and H.245 messages containing a protocolIdentifier= {itu-t (0) recommendation (0) h (8) 245 version (0) x}, where "x" is 3 or higher.

The procedures and the signalling protocol of this Recommendation are derived from the Call Intrusion supplementary service specified in ISO/IEC 14845 and ISO/IEC 14846.