VoIP Gateway Apparatus, And Method For Controlling Call-In/Call-Out in VoIP Gateway Apparatus

摘要

A VoIP gateway apparatus is used to provide an IP centrex service to accommodated devices. The VoIP gateway apparatus (1) assigns, to a call originated from an accommodated device (PBX2), a telephone number for which the number of simultaneous call connections has not reached a simultaneous connection tolerance number, and sends the call to an IP centrex network (5) with the assigned telephone number used as a calling number. The VoIP gateway apparatus (1) includes a number-of-calls management part (105) and a SIP processing part (104). The number-of-calls management part (105) manages the number of the current simultaneous call connections for each of the telephone numbers as assigned to the apparatus. When a call is received from an accommodated device, a SIP processing part (104) selects, among the telephone numbers as assigned to the apparatus, a telephone number, for which the number of the current simultaneous call connections as managed by the number-of-calls management part (105) is smaller than the predetermined simultaneous connection tolerance number, and then transmits, to the IP centrex network (5), a SIP packet of a call control message to which the selected telephone number has been added as the calling number.