Patent ID: 7952995

Claim:
A system to provide Voice over Internet Protocol (VoIP) service, the system comprising: a plurality of Internet Protocol (IP) terminals connected to a network, at least one of said plurality of IP terminals to generate a test message and to provide the test message to the network, the test message comprising port information used when receiving and transmitting packets; and a switching system to store and manage the port information of the at least one IP terminal provided by the test message, to transmit port information of one of a transmitting IP terminal and a receiving IP terminal if VoIP service for the receiving IP terminal in a private network is requested, and to allow each of the plurality of IP terminals to receive and transmit the packets using the transmitted port information, wherein the stored port information comprises port information corresponding to a port used for exchanging voice packets and port information corresponding to a port used for exchanging signaling packets, and wherein the switching system comprises: a reception unit to receive the test message, the voice packets, and a VoIP service request message transmitted from the transmitting IP terminal; a port management unit to manage phone number information, IP address information, and port information of the transmitting IP terminal through the test message received by the reception unit; a storage unit to store information managed in the port management unit; and a port processing unit to search for the port information of the transmitting IP terminal from the storage unit, the searched port information of the transmitting IP terminal being provided in the VoIP service request message, to transmit the VoIP service request message to the receiving IP terminal in response to the VoIP service request message being transmitted from the transmitting IP terminal, to search for the port information of the receiving IP terminal from the storage unit, providing the searched port information of the receiving IP terminal in a response message, and to transmit the response message to the transmitting IP terminal in response to the response message being transmitted from the receiving IP terminal, and wherein no portion of the test message is transmitted by the switching system.