COMMUNICATION DEVICE

摘要

In the position registration releasing procedure of MobilePv6, in case a response to a position registration releasing request cannot be received in a mobile communication terminal (MN), the position registration releasing operation is completed in either a position managing device (HA) or a communication device (CN) to act as a communication partner of the mobile communication terminal, but the position registration releasing operation cannot be completed at the mobile communication terminal (MN) so that the communication cannot be continued. A BU (seq N) (151) is sent from the MN (25) to the HA (23). Here, the HA (23) is characterized in that it controls the MN (25) to send the BA without fail to the MN (25) in any case it receives the BU (151). In this case, the HA (23) regulates the MN (25) to send a BA (161), in case it receives a BU (157) for the position registration release from the MN (25), no matter whether or not a position registration releasing operation (158) at the HA might have been completed. As a result, the MN (25) is enabled, by receiving the BA, to delete the Binding Update List thereby to complete the position registration releasing operation. Next, the MN sends a message indicating the end of the position registration releasing operation, newly to the BA of the response of the position registration release from the HA/CN. This HA/CN performs the position registration releasing operation in response to the message indicating the position registration releasing operation from the MN. This MN completes the position registration releasing operation when it detects an abnormal state, in which the position registration releasing operation is completed in the HA/CN but not in the MN.