Patent ID: 7475144

Claim:
A mobile Internet Protocol (IP) system, comprising: a mobile node initially linked to a first foreign network; a home agent receiving a set of data packets, which are supposed to be transmitted to said mobile node, said home agent being included in a home network of said mobile node; a first foreign agent receiving said packets from said home agent and storing said packets in a first buffer of said first foreign agent, wherein said first foreign agent sends said stored packets to said mobile node if said mobile node continues to be linked to said first foreign network; and a second foreign agent receiving said packets stored in said first buffer of said first foreign agent from said first foreign agent, and the second foreign agent storing said received packets in a second buffer of said second foreign agent if said mobile node is moved to a second foreign network from said first foreign network, the packets stored in the second buffer that are received from the first buffer include packets stored in the first buffer while the mobile node is linked to the first foreign network, said second foreign agent being included in said second foreign network, wherein the first foreign agent keeps storing the data packets being sent from the home agent until the first foreign agent receives a notification message from the mobile node, and the notification message received at the first foreign agent informs the first foreign agent that the mobile node has moved to another foreign agent, and wherein the packets stored in the first buffer of the first foreign agent are directly sent by the first foreign agent to the second foreign agent indicated in the notification message.