A gateway apparatus for a Radio over IP, RoIP, network, comprising: a secure memory; a first communication interface configured to provide an interface that transmits and receives data to and from a plurality of terminals in the RoIP network; a second communication interface configured to provide an interface that transmits and receives data to and from a home subscriber server of a mobile communication network; and an operation processor configured to perform: 'a' obtaining apparatus information, wherein the apparatus information includes unique identification information of the gateway apparatus or unique identification information of a designated terminal among the plurality of terminals; 'b' registering the apparatus information in the home subscriber server through the second communication interface, receiving virtual subscriber identity module, SIM, information including a mobile identification number from the home subscriber server through the second communication interface, and storing the received virtual SIM information in the secure memory; and 'c' providing, based on the mobile identification number, a service associated with the mobile communication network for at least one terminal among the plurality of the terminals in the RoIP network through the first communication interface, wherein, when the apparatus information includes unique identification information of the gateway apparatus, 'c' includes 'c-3' selecting, among the plurality of terminals in the RoIP network, one or more terminals to which the service associated with the mobile communication network is to be provided and, when the apparatus information includes the unique identification information of the designated terminal among the plurality of terminals, 'c' includes 'c-1' providing the service associated with the mobile communication network for the designated terminal in the RoIP network and/or 'c-2' providing the service associated with the mobile communication network to a terminal group including the designated terminal among the terminals in the RoIP network. a secure memory; a first communication interface configured to provide an interface that transmits and receives data to and from a plurality of terminals in the RoIP network; a second communication interface configured to provide an interface that transmits and receives data to and from a home subscriber server of a mobile communication network; and an operation processor configured to perform: 'a' obtaining apparatus information, wherein the apparatus information includes unique identification information of the gateway apparatus or unique identification information of a designated terminal among the plurality of terminals; 'b' registering the apparatus information in the home subscriber server through the second communication interface, receiving virtual subscriber identity module, SIM, information including a mobile identification number from the home subscriber server through the second communication interface, and storing the received virtual SIM information in the secure memory; and 'c' providing, based on the mobile identification number, a service associated with the mobile communication network for at least one terminal among the plurality of the terminals in the RoIP network through the first communication interface, 'a' obtaining apparatus information, wherein the apparatus information includes unique identification information of the gateway apparatus or unique identification information of a designated terminal among the plurality of terminals; 'b' registering the apparatus information in the home subscriber server through the second communication interface, receiving virtual subscriber identity module, SIM, information including a mobile identification number from the home subscriber server through the second communication interface, and storing the received virtual SIM information in the secure memory; and 'c' providing, based on the mobile identification number, a service associated with the mobile communication network for at least one terminal among the plurality of the terminals in the RoIP network through the first communication interface, wherein, when the apparatus information includes unique identification information of the gateway apparatus, 'c' includes 'c-3' selecting, among the plurality of terminals in the RoIP network, one or more terminals to which the service associated with the mobile communication network is to be provided and, when the apparatus information includes the unique identification information of the designated terminal among the plurality of terminals, 'c' includes 'c-1' providing the service associated with the mobile communication network for the designated terminal in the RoIP network and/or 'c-2' providing the service associated with the mobile communication network to a terminal group including the designated terminal among the terminals in the RoIP network.