A delivery node alternately connects to a first wireless terminal and a second wireless terminal. When a first packet with a virtual IP address of the second wireless terminal as a destination IP address is output from a first application to a virtual network interface, the first wireless terminal encapsulates the first packet with the use of an encapsulation header and transmits to the delivery node. The delivery node encapsulates the first packet obtained by decapsulating the received encapsulation packet again, and transmits to the second wireless terminal. The second wireless terminal transmits the first packet obtained by decapsulating the received encapsulation packet to a second application through a virtual network interface.