| 摘要 |
<p>An SGSN (4) for relaying communication data by a mobile communication terminal (2) when the mobile communication terminal (2) is to implement mobile communication, and provided with: a receiving unit (42); a communication volume balance storage unit (41) for storing communication volume balance information indicating the remaining communication time or the remaining communication data volume which can be used for mobile communications by the mobile communication terminal (2); and a communication volume balance updating unit (43) that updates the communication volume balance information. When the communication volume balance updating unit (43) receives requests to start or finish mobile communication by the mobile communication terminal (2) or another exchange, the communication volume balance updating unit (43) starts or finishes updating the communication volume balance information on the basis of data communications by the mobile communication terminal (2), and when the communication volume balance updating unit (43) receives request to set up or cancel a preservation state while the mobile communication terminal (2) or another exchange is communicating, the communication volume balance updating unit (43) stops or starts updating the communication volume balance information on the basis of data communications by the mobile communication terminal (2).</p> |
