Patent ID: 8750220

Claim:
A gateway device, comprising: a signaling transceiver unit adapted to transmit and receive a signaling message; a storage unit adapted to store an International Mobile Subscriber Identifier, IMSI, number segment of a first operator and an IMSI number segment of a second operator reserved for an international roaming subscriber of the first operator by the second operator; and a control unit adapted to forward a signaling message received by the signaling transceiver unit to a roaming processing device upon determining that an IMSI carried in the signaling message is included in the IMSI number segment of the first operator or the IMSI number segment of the second operator, and forward, through the signaling transceiver unit, a signaling message returned from the roaming processing device, wherein the control unit is further adapted to modify a source address of a signaling message from a first operator network to an identifier of a gateway device of the second operator, modify a destination address of the signaling message from the first operator network to an identifier of a gateway device of a third operator, modify a source address of a signaling message from a third operator network, where the international roaming subscriber of the first operator roams, to the identifier of the gateway device of the second operator, and modify a destination address of the signaling message from the third operator network to an identifier of a gateway device of the first operator.