Handover method in mobile communication system and router device used in mobile communication system

A handover method used when a mobile node to which a first address is assigned in a communication area of a first router device travels from the communication area of the first router device to a communication area of a second router device, comprising:

• storing a packet addressed to the mobile node in the second router device until the second router device and the mobile node is connected;
• and
• reading the stored packet in a transmitted order by a correspondent node to transmit to the mobile node.

A router device that is used in a mobile communication system including a plurality of router devices as a first router device among the plurality of router devices, comprising:

• predicting means for predicting that a mobile node to which a first address is assigned in a communication area of the first router device travels from the communication area of the first router device to a communication area of a second router device;
• and
• transmitting means for transmitting, when a second address to be used in the communication area of the second router device is assigned to the mobile node according to the prediction, a message for transferring a packet addressed to the first address to the second address to a third router device located in a node where a route from a correspondent node with which the mobile node is communicating to the first router device and a route from the correspondent node to the second router device overlap.

A router device that is used in a mobile communication system including a plurality of router devices as a first router device among the plurality of router devices, comprising:

• a predicting unit predicting that a mobile node to which a first address is assigned in a communication area of the first router device travels from the communication area of the first router device to a communication area of a second router device;
• and
• a transmitting unit transmitting, when a second address to be used in the communication area of the second router device is assigned to the mobile node according to the prediction, a message for transferring a packet addressed to the first address to the second address to a third router device located in a node where a route from a correspondent node with which the mobile node is communicating to the first router device and a route from the correspondent node to the second router device overlap.