Inter-network connection relay device and method for different kind of networks

A hybrid network access repeater and a method thereof are provided to connect a previously registered user terminal to a hybrid network by accessing an associated network access authentication server according to a hybrid network access request, converting an allocated public IP address into a private IP address, delivering it to the user terminal so that the user terminal can access the associated network, and relaying data between the user terminal and the associated network through the protocol conversion. An access repeat control part in a hybrid network access repeater comprises a WiFi registration manager(21), a Zigbee registration manager(22), and a WiBro-WiFi protocol converter(23). The WiFi registration manager(21) confirms that a WiFi terminal has been registered, and informs a WiFi modem(13) or a WiBro modem(14) of it. The zigbee registration manager(22) confirms that a Zigbee terminal has been registered, and informs the WiFi modem(13) or the WiBro modem(14) of it. The WiBro-WiFi protocol converter(23) converts protocol 802.16-formatted data, transferred from the WiBro modem(14), into protocol 802.11-formatted data and transmits the converted data to an associated WiFi terminal through a WiFi access point(11). Also the WiBro-WiFi protocol converter(23) converts protocol 802.11-formatted data, transferred from the WiFi access point(11), into protocol 802.16-formatted data and transmits the converted data to the WiBro modem(14).