Mobile IP system and data routing method of the same

• US 7,475,144 B2
• Filed: 11/13/2001
• Issued: 01/06/2009
• Est. Priority Date: 11/14/2000
• Status: Expired due to Fees

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Oh, Suk Sang
• Primary Examiner(s): Barqadle; Yasin M
• Application Number:
  US09/987,098
• Publication Number:
  US 20020059433A1
• Time in Patent Office: 2,611 Days
• Field of Search: 709202-203, 709226-231, 709/245, 455/466, 370/331, 370/328, 370/355, 370/401
• US Class Current: 709/227
• CPC Class Codes: H04W 36/0011 for data sessions of end-to-end connection
• CPC Class Codes: H04W 36/0019 adapted for mobile IP [MIP]
• CPC Class Codes: H04W 36/02 Buffering or recovering information during reselection ; Modification of the traffic flow during hand-off
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]

Abstract

A mobile Internet Protocol (IP) system and a data routing method of the mobile IP system are disclosed. According to the present invention, even if a mobile node moves from a first foreign agent to a second foreign agent while it receives data packets from the first foreign agent, the first foreign agent keeps storing the data packets it its buffer, and it sends the stored data to the second foreign agent indicated in a notification message received from the mobile node. Therefore, the host does not need to retransmit the data packets to the second foreign agent again. This will greatly increase reliability of the data transmission in the IP system and can reduce the overhead of the whole system.

Claims

1. 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.

2. The mobile IP system of claim 1, wherein said first foreign agent deletes said stored packets after sending said stored packets to said second foreign agent.

3. The mobile IP system of claim 1, wherein said second foreign agent deletes said stored packets after sending said stored packets to said mobile node.

4. The mobile IP system of claim 1, wherein said first buffer is coupled to said first foreign agent.

5. The mobile IP system of claim 1, wherein said first foreign agent determines whether said mobile node is moved to said second foreign network by checking whether the notification message is received from said mobile node.

6. A method of transmitting data in a mobile Internet Protocol (IP) network, the method comprising:

transmitting a set of data packets from a host to a home agent of a mobile node, said mobile node being currently linked to a first foreign network having a first foreign agent;

sending said packets received by said home agent to said first foreign agent and the foreign agent storing the packets in a first buffer of the first foreign agent;

sending the stored packets by the first foreign agent to the mobile node if the mobile node continues to be linked to the first foreign network;

moving said mobile node from the first foreign network to a second foreign network having a second foreign agent;

sending said packets stored in said first buffer by the first foreign agent to said second foreign agent and the second foreign agent storing the received packets in a second buffer if said mobile node is moved to the second foreign network from the first foreign network, wherein 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 provided in the first foreign network; and

transmitting said packets stored in said second buffer of the second foreign agent to said mobile node,

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 stored packets in the first buffer of the first foreign agent are directly sent by the first foreign agent to the second buffer of the second foreign agent indicated in the notification message.

7. The method of claim 6, wherein said first buffer is coupled to said first foreign agent.

8. The method of claim 6, wherein said second buffer is coupled to said second foreign agent.

9. The method of claim 6, further comprising deleting said packets stored in said first buffer after sending said packets stored in said first buffer to said second foreign agent.

10. The method of claim 6, further comprising deleting said packets stored in said second buffer after transmitting said packets stored in said second buffer to said mobile node.

11. A data routing method at a first foreign agent of a first foreign network in a mobile Internet Protocol (IP) network, the method comprising:

receiving a set of data packets at a home agent, wherein the data packets are transmitted from a host to the home agent;

determining a mobile node to which said packets are supposed to be transmitted;

storing packets in a first buffer of the first foreign agent until a notification message is received at the first foreign agent from the mobile node, wherein the notification message received at the first foreign agent informs the first foreign agent that the mobile node has moved to another foreign agent;

sending the stored packets from the first buffer to the mobile node if the mobile node is still linked to the first foreign network;

if the mobile node is not linked to the first foreign agent, determining if said mobile node moves to a second foreign network having a second foreign agent; and

sending the stored packets from the first buffer to the second foreign agent when the notification message is received at the first foreign agent from the mobile node,

wherein the second foreign agent receives the packets from the first buffer of the first foreign agent and stores the packets in a second buffer of the second foreign agent after the mobile node has moved from the first foreign network to the second foreign network, and the second foreign agent transmits the stored packets in the second buffer to the mobile node,

wherein the packets stored in the second buffer that are received from the first buffer of the first foreign agent include packets stored in the first buffer while the mobile node is in the second foreign network and prior to the first foreign agent receiving the notification message from the mobile node.

12. The method of claim 11, further comprising deleting said packets stored in said first buffer after sending said packets stored in said first buffer to said second foreign agent.

13. The method of claim 11, further comprising deleting said packets stored in said second buffer after transmitting said packets stored in said second buffer to said mobile node.

14. The method of claim 11, wherein said first buffer is coupled to said first foreign agent.

15. The method of claim 11, wherein said determining is performed by checking whether the notification message is received from said mobile node.

16. The method of claim 11, wherein an IP address of said second foreign agent is included in the notification message.