METHOD FOR CONTROLLING GROUP TERMINATING CALL IN VOICE OVER INTERNET PROTOCOL SYSTEM

摘要

PURPOSE: A group termination call control method in a VoIP(Voice over Internet Protocol) system is provided to maintain compatibility with an H.323 system without a group termination function by not correcting a protocol. CONSTITUTION: In a first stage, when a caller makes a call in a group, a group number is contained in a recipient number field of an ARQ(Admission Request) message of the caller, and the ARQ message is transferred to a gate keeper. The gate keeper checks whether a recipient number is in general terminal information or in group information. If the recipient number is in the group information, the gate keeper senses a group termination. The gate keeper checks whether a group state is valid, and if valid, the gate keeper transfers an ACF(Admission Request Confirm) message to the caller. In a second stage, the caller transfers a setup message to the gate keeper to set up a call. Upon receiving the setup message, the gate keeper transfers a call proceeding/alerting message to the caller. The gate keeper searches a member in an idle state from a group corresponding to the group number and transfers the setup message to an EP A and EP B in the idle state. In a third stage, each member of the corresponding group, which has received the setup message, undergoes a call setup process independently. In a fourth stage, when the EP B first receives a call, it transfers a connect message to the gate keeper. Then, the gate keeper transfers the connect message to the caller, and transfers a release complete message to the member EP A to stop its call setup procedure.