To distribute routes to a public network by managing an IP address corresponding to a B-channel, for executing plural calls in the same MAC in a resource management circuit for executing communication in LAN emulation.

A resource management circuit 10 receiving an IP address request acquires the IP address which Bch-corresponds to a public line 16 and transmits the IP address to a frame conversion control circuit 13 in a public network gateway device 15 and an application 2a in a client 1a. The control circuit 13 receiving the IP address generates Bch of the public line 16 and the management table of the IP address. The application 2a generates a data transmission request and transmits it by using a MAC address and the IP address, which are information in a received IP address notice. The control circuit 13 receiving it specifies the Bch number of the line 16, which is to be transmitted from the opposite address, and transmits a data frame.