Patent ID: 7447186

Claim:
In a Home Agent supporting Mobile IP, a method of notifying a Correspondent Node of a Mobile Node's location, thereby enabling the Correspondent Node to communicate directly with the Mobile Node, comprising: receiving a HOTi message protected in IPSec transport mode from the Mobile Node; modifying the HOTi message and transmitting the modified HOTi message to the Correspondent Node; receiving a HOT message from the Correspondent Node; and modifying the HOT message and transmitting the modified HOT message to the Mobile Node, wherein the modified HOT message is protected in IPSec transport mode, wherein the HOTi message includes a source address equal to a care-of address of the Mobile Node, a destination option equal to the Mobile Node's home address, and an extra option including an address of the Correspondent Node, and the modified HOTi message includes a source address equal to the Mobile Node's home address and a destination address equal to the address of the Correspondent Node, wherein modifying the HOTi message comprises: removing the destination option and the extra option replacing the source address with the Mobile Node's home address obtained from the destination option; and replacing the destination address with the address of the Correspondent Node obtained from the extra option.