Patent ID: 7116654

Claim:
A route optimization method in a mobile Internet Protocol system using a mobile Internet Protocol, the method comprising: sending a registration request message containing a care-of address to a home agent through a foreign agent when a mobile host is assigned to the care-of address corresponding to a changed point of access to the Internet, the home agent being a part of a home network for the mobile host to access the Internet, the foreign agent being a part of a foreign network for the mobile host to access the Internet, the home agent being distinguishable from the foreign agent; storing the care-of address in an internal domain name server database by the home agent, the care-of address being stored to correspond to domain name of the mobile host; when a query by domain name about the mobile host is received from a correspondent node, sending the care-of address corresponding to the domain name of the mobile host together with caching prevention information to the correspondent node from the home agent, the caching prevention information being set to prevent the correspondent node from caching the care-of address of the mobile host, the caching prevention information being set to prevent any domain name server from caching the care-of address of the mobile host; and communicating with the mobile host by the correspondent node using the care-of address corresponding to the domain name of the mobile host.