INTERWORKING APPARATUS AND METHOD FOR TRANSMITTING INTERNET PHONE PACKET BY USING AAL2 FUNCTION OF ATM NETWORK

PURPOSE: An interworking apparatus and a method for transmitting an Internet phone packet by using an AAL2 function of an ATM network are provided to guarantee a quality of service(QoS) by connecting a channel by using an AAL2 function of the existing ATM network adopting a QoS technique and adopting a VoIP technique by using the Internet to a local network, and adopting a technique such as a VTOA through an interworking function to a backbone network, and reduce an investment amount by improving a utilization of the ATM network. CONSTITUTION: A router(41) of the Internet is connected to a subscriber(1). A subscriber(7) is connected to a router(42) of the other party by using an ATM network through an IWF(Interworking Function)(10,20), and the router(42) is connected to the terminating party. If the subscriber(1) connected to the originating router(41) wants to make a phone cal to the subscriber(7) connected to the terminating router(42), the subscriber(1) dials a phone number of the subscriber(7). The phone number is recognized by a call manger(3) of the originating router(41). The call manager(3) transmits a call set-up message to the ATM IWF(10). At this time, the call manager assigns an IP address and a UDP port for communication between the originating terminal and the IWF. Upon receipt of the call set-up message, the ATM IWF(10) searches the ATM IWF(20) having the termination number on the ATM, and establishes a connection to the terminating IWF(20). The terminating IWF(20) renders a call manager(5) of the terminating router(42) to call a terminal(7) having the terminating number. When a call is available, he call manager(5) of the terminating router(42) assigns an IP address and a UDP address for communication between the IWF and the terminating terminal(7). While the bell is ringing to the called terminating terminal(7), the call manager(5) of the terminating router(42) transmits a message that it is calling to the originating party in the reverse order. And then, when the terminating terminal(7) answers, a response message is transmitted to the originating party, thereby completing a call connection between terminals.