Patent ID: 8526956

Claim:
A method for controlling a network system, wherein a mobile terminal performs a handover from a first network to a second network during data transmission and/or reception through an existing data transmission tunnel between a router and an access point within the first network, comprising: transmitting a message, during employment of the existing data transmission tunnel, requesting a transmission bandwidth change of the data transmission and/or reception to a transmission bandwidth supported in the second network, from the mobile terminal to a server after performing the handover; changing the transmission bandwidth of the data transmission and/or reception to the transmission bandwidth supported by the second network based on the transmitted message requesting the transmission bandwidth change; transmitting a message acknowledging a changing of the transmission bandwidth of the data transmission and/or reception, from the server to the router, after the changing of the transmission bandwidth of the data transmission and/or reception; and transceiving data through a new data transmission tunnel between the router and an access point within the second network based on the message acknowledging the changing of the transmission bandwidth of the data transmission and/or reception.