DATA COMMUNICATION METHOD USING A PROXY SERVER IN AN IP NETWORK, PARTICULARLY CONCERNED WITH SETTING AN RTP SESSION BETWEEN IP TERMINALS THROUGH A SPECIFIC TRANSMISSION PROXY SERVER

摘要

PURPOSE: A data communication method using a proxy server in an IP network is provided to transmit IP packets sent between IP terminals through a random transmission proxy server designated by an SIP proxy server, thereby enabling accounting/session controls by measuring the number of packets processed by the transmission proxy server. CONSTITUTION: The first terminal(11) transmits an invite message to an SIP proxy server(13)(S41). The server(13) transmits the invite message to the second terminal(12)(S42). The second terminal(12) transmits a response message to the server(13)(S43). The server(13) transmits the response message to the first terminal(11)(S44). The first terminal(11) sends a response confirm message to the server(13)(S45). The server(13) sends the confirm message to the second terminal(12)(S46). A bidirectional RTP(Real Time Protocol) session is set between the terminals(11,12)(S47). An IP packet having a capsulated external header is transmitted to a transmission proxy server(14)(S51). The proxy server(14) transmits the IP packet where the external header is removed to an IP network(S52). The second terminal(12) transmits an IP packet having a capsulated header to the server(14)(S53). The server(14) sends the IP packet where the header is removed to the IP network(S54).