Patent ID: 8730907

Claim:
A network system comprising: a mobile node; a correspondent node for transmitting/receiving a data packet to/from the mobile node; a first router to which the mobile node is coupled at a visited domain; and a second router to which the mobile node couples to when the mobile node moves from the first router, wherein the second router has a location registration message generating unit for generating a location registration message of the mobile node including a first network address allocated to the mobile node when coupled to the first router before the mobile node moves and a second network address allocated to the mobile node when coupled to the second router after the mobile node moves and transmitting the location registration message to the first router, the first router including: a binding cache; a movement managing unit for receiving the location registration message and storing into the binding cache the first network address allocated to the mobile node when coupled to the first router before the mobile node moves and the second network address allocated to the mobile node when coupled to the second router after the mobile node moves; and an encapsulating unit for receiving a data packet from the correspondent node, generating an encapsulated data packet by encapsulating the data packet, and transmitting the encapsulated data packet designated as a transmission destination the second network address which is stored in the binding cache after the move, wherein the mobile node includes a decapsulating unit for receiving the encapsulated data packet and decapsulating the encapsulated data packet.