Patent ID: 7161913

Claim:
A method for transmitting a data packet from a mobile node to a correspondent node through a foreign agent while maintaining security therebetween, in a communication system including the mobile node having a unique mobile IP (Internet Protocol) address, the foreign agent wirelessly connected to the mobile node, the foreign agent having a unique IP address, a home agent capable of performing bi-directional wire communication with the foreign agent, the home agent having mapped information of the mobile IP address of the mobile node and the IP address of the foreign agent, and the correspondent node capable of performing bi-directional wire communication with the home agent, the method comprising the steps of: receiving in the correspondent node the IP address of the foreign agent, mapped with the mobile IP address of the mobile node through the home agent; and transmitting tunneling indication information indicating whether the correspondent node can decapsulate a data packet encapsulated by the foreign agent, from the correspondent node to the foreign agent having the IP address.