System and method for enabling fault tolerant H.323 systems

摘要

An H.323 client terminal (102) according to an embodiment of the invention employs primary and secondary H.323 control units or state machines (110a, 110b). The primary control unit (110a) sends signaling messages to a primary gatekeeper (108a) and triggers the secondary control unit (110b) to send a message with an appropriate correlation identifier to a secondary gatekeeper (108b). The primary control unit (110a) establishes a call per standard H.323 protocols. The secondary control unit (110b) also establishes a call via a secondary gatekeeper (108b). However, no media channels are established for this back up call. As the secondary control unit (110b) receives signaling from the secondary gatekeeper (108b), it checks the status of the call with the primary control unit (110a). If the call signaling on the primary control unit (110a) is proceeding normally, no further action is taken. If the call signaling with the primary gatekeeper (108a) fails, the secondary control unit (110b) takes over communication.