COMMUNICATION METHOD BETWEEN INTERNET KEYPHONE SYSTEMS HAVING VOICE OVER INTERNET PROTOCOL FUNCTION

摘要

PURPOSE: A communication method between Internet keyphone systems having a VoIP(Voice over Internet Protocol) function is provided to smoothly transmit and receive data using a VoIP by adding VoIP IP address information, VoIP port information, router IP address information and router port information for received data to a NAT(Network Address Translation) table embedded in a router. CONSTITUTION: The first router having the first NAT table transmits a setup message to the second router by a TCP/IP protocol. The second router transmits the receiving confirmation message of the setup message to the first router. The second router transmits a call setup complete message to the first router, and the port number of a message necessary to set up a transmission channel of voice data is registered in the second NAT table and the first NAT table. The first router transmits the transmission channel setup request message to the second router, and a transmission protocol associated message port of the voice data and a transmission control protocol associated message port of the data are registered in the first NAT table. The second router transmits a channel setup complete message to the first router, and a transmission protocol associated message port number and a transmission control protocol associated message port number are registered in the second NAT table. As a transmission protocol message and a transmission control protocol message are exchanged through the transmission protocol message port and the transmission control protocol message port, the transmission of the voice data and the voice data control message is carried out.