A communication system, in which a mobile terminal uses a data path that was generated with an ISP network by a base station in a home network to access a NW via the ISP network, includes an authentication means and connection control means in the ISP network. The base station accepts an access request from the mobile terminal and transmits information relating to the base station and the mobile terminal to the connection control means. The authentication means determines based on the information whether a linking service that connects to the home NW without traversing the ISP network can be provided to the mobile terminal, and if the linking service can be provided, notifies this information to the connection control means. Based on this notification, the connection control means requests the base station to generate a data path for providing the linking service, and the base station generates the data path.