Mobile communication scheme without home agents for supporting communications of mobile nodes

• US 6,904,466 B1
• Filed: 05/19/2000
• Issued: 06/07/2005
• Est. Priority Date: 05/20/1999
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Ishiyama, Masahiro, Inoue, Atsushi
• Primary Examiner(s): Etienne, Ario
• Assistant Examiner(s): EL CHANTI, HUSSEIN A
• Application Number:
  US09/573,189
• Time in Patent Office: 1,845 Days
• Field of Search: 709206-207, 709/203, 709223-224, 709/228, 709/238, 709/242, 709/245, 709/204, 709/205
• US Class Current: 709/245
• CPC Class Codes: H04L 63/164 at the network layer
• CPC Class Codes: H04W 8/26 Network addressing or numbering for mobility support
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]

Abstract

The disclosed mobile communication scheme enables easy change of a connected location of a mobile computer on the IP network when the mobile computer leaves its home network, without requiring the use of a home agent, while providing a sufficient level of security. The mobile computer transmits a packet from a visited site network to a correspondent by encapsulating an inner packet having a home address as an original source address within an outer packet having a current location address as a source address. The correspondent which received this encapsulated packet recognizes the source addresses of the outer and inner packets of the encapsulated packet as the current location address and the home address of the mobile computer, respectively, so that the correspondent can transmit a packet to the mobile computer thereafter by encapsulating an inner packet having the home address as a final destination address within an outer packet having the current location address as a destination address.

Claims

1. A method of mobile communications between a mobile computer capable of carrying out communications while moving over inter-connected networks and a correspondent computer, the method comprising the steps of:

transmitting a packet directly to the correspondent computer from the mobile computer located at a visited site network outside a home network of the mobile computer, by encapsulating an inner packet having a home address assigned to the mobile computer at the home network as a source address, within an outer packet having a current location address acquired at the visited site network as a source address;

storing cryptosystem parameter information necessary in forming a tunnel for transferring an encapsulated packet by encrypting the inner packet, at the mobile computer and the correspondent computer;

notifying a change of the current location address of the mobile computer directly from the mobile computer to the correspondent computer by setting a new current location address as the source address of the outer packet in the packet transmitted by the transmitting step;

updating the current location address used as a termination endpoint address of the tunnel in the cryptosystem parameter information stored at the mobile computer into the new current location address, when the current location address is changed to the new current location address;

managing source addresses of the outer packet and the inner packet of the encapsulated packet received directly from the mobile computer respectively as the current location address and the home address of the mobile computer at the correspondent computer; and

updating the current location address used as a termination endpoint address of the tunnel in the cryptosystem parameter information stored at the correspondent computer into the new current location address, when the change of the current location address to the new current location address is notified from the mobile computer.

2. A method of mobile communications between a mobile computer capable of carrying out communications while moving over inter-connected networks and a correspondent computer, the method comprising the steps of:

storing a current location address acquired by the mobile computer at a visited site network outside a home network of the mobile computer, and a home address assigned to the mobile computer at the home network, in correspondence to a host name of the mobile computer, at a computer management device;

updating the current location address stored at the computer management device, according to a notification regarding the current location address received directly from the mobile computer;

making an inquiry about the mobile computer directly from the correspondent computer to the computer management device, before initiating a packet transmission to the mobile computer at the correspondent computer;

returning a response from the computer management device in response to the inquiry for the current location address of the mobile computer and the home address of the mobile computer received directly from the correspondent computer; and

transmitting a packet directly from the correspondent computer to the mobile computer located at the visited site network, by encapsulating an inner packet having the home address as a destination address, within an outer packet having the current location address as a destination address, when the current location address and the home address are obtained from the computer management device in response to the inquiry made by the correspondent computer.

3. A mobile computer device capable of carrying out communications while moving over inter-connected networks, the mobile computer device comprising:

a packet transmission unit configured to transmit a packet directly to a correspondent computer from a visited site network outside a home network of the mobile computer device, by encapsulating an inner packet having a home address assigned to the mobile computer device at the home network as a source address, within an outer packet having a current location address acquired at the visited site network as a source address;

a memory configured to store cryptosystem parameter information necessary in forming a tunnel for transferring an encapsulated packet by encrypting the inner packet; and

a current location address management unit configured to notify a change of the current location address of the mobile computer device directly to the correspondent computer by setting a new current location address as the source address of the outer packet in the packet transmitted by the packet transmission unit, and to update the current location address used as a termination endpoint address of the tunnel in the cryptosystem parameter information stored in the memory into the new current location address, when the current location address is changed to the new current location address.

4. The mobile computer device of claim 3, wherein the current location address management unit also notifies the new current location address to a computer management device that manages the home address of the mobile computer device when the current location address is changed to the new current location address.

5. The mobile computer device of claim 3, further comprising a setting unit configured to set the cryptosystem parameter information with respect to the correspondent computer in the memory,

wherein the current location address management unit updates only a portion corresponding to the current location address of the mobile computer device in the cryptosystem parameter information already set in the memory by the setting unit into the new current location address when the current location address is changed to the new current location address.

6. A computer management device provided in inter-connected networks on which a mobile computer carries out communications while moving over the inter-connected networks, the computer management device comprising:

a memory configured to store a current location address acquired by the mobile computer at a visited site network outside a home network of the mobile computer, and a home address assigned to the mobile computer at the home network, in correspondence to a host name of the mobile computer; and

a management unit configured to update the current location address stored in the memory according to a notification regarding the current location address received directly from the mobile computer, and to respond to an inquiry for the current location address of the mobile computer and an inquiry for the home address of the mobile computer received directly from a correspondent computer of the mobile computer.

7. The computer management device of claim 6, wherein the memory stores an entry for the mobile computer which includes a first field storing a correspondence between the host name and the current location address of the mobile computer, and a second field storing the home address of the mobile computer in correspondence to the first field, and the management unit responds to the inquiry for the current location address by referring to the first field and to the inquiry for the home address by referring to the second field.

8. The computer management device of claim 7, wherein the first field stores the home address of the mobile computer when the mobile computer is located in the home network, or the current location address acquired at the visited site network as notified from the mobile computer when the mobile computer is located outside the home network.

9. A correspondent computer device for carrying out communications with a mobile computer which is capable of carrying out communications while moving over inter-connected networks, the correspondent computer comprising:

a memory configured to store cryptosystem parameter information necessary in forming a tunnel for transferring an encapsulated packet with respect to the mobile computer; and

a mobile computer address management unit configured to manage source addresses of an outer packet and an inner packet of the encapsulated packet received directly from the mobile computer respectively as a current location address acquired by the mobile computer at a visited site network outside a home network of the mobile computer and a home address assigned to the mobile computer at the home network, and to update the current location address used as a termination endpoint address of the tunnel in the cryptosystem parameter information stored in the memory into a new current location address, when a change of the current location address to the new current location address is notified directly from the mobile computer.

10. The correspondent computer device of claim 9, wherein the mobile computer address management unit recognizes the change of the current location address from a change in a source address of the outer packet in the encapsulated packet received from the mobile computer.

11. The correspondent computer device of claim 9, further comprising:

a packet transmission unit configured to transmit a packet to the mobile computer located at the visited site network, by encapsulating an inner packet having the home address as a destination address, within an outer packet having the current location address as a destination address.

12. A correspondent computer device for carrying out communications with a mobile computer which is capable of carrying out communications while moving over inter-connected networks, the correspondent computer comprising:

a mobile computer address management unit configured to make an inquiry about the mobile computer directly to a computer management device that manages a current location address acquired by the mobile computer at a visited site network outside a home network of the mobile computer and a home address assigned to the mobile computer device at the home network, before initiating a packet transmission to the mobile computer; and

a packet transmission unit configured to transmit a packet directly to the mobile computer located at the visited site network, by encapsulating an inner packet having the home address as a destination address, within an outer packet having the current location address as a destination address, when the current location address and the home address are obtained from the computer management device in response to the inquiry made by the mobile computer address management unit.

13. A computer program product for causing a computer to function as a mobile computer device capable of carrying out communications while moving over inter-connected networks, the computer program product comprising:

a first computer readable program code for causing said computer to transmit a packet directly to a correspondent computer from a visited site network outside a home network of the mobile computer device, by encapsulating an inner packet having a home address assigned to the mobile computer device at the home network as a source address, within an outer packet having a current location address acquired at the visited site network as a source address;

a second computer readable program code for causing said computer to store cryptosystem parameter information necessary in forming a tunnel for transferring an encapsulated packet by encrypting the inner packet; and

a third computer readable program code for causing said computer to notify a change or the current location address of the mobile computer device directly to the correspondent computer by setting a new current location address as the source address of the outer packet in the packet transmitted by the first computer readable program code, and to update the current location address used as a termination endpoint address of the tunnel in the cryptosystem parameter information stored by the second computer readable program code into the new current location address, when the current location address is changed to the new current location address.

14. A computer program product for causing a computer to function as a computer management device provided in inter-connected networks on which a mobile computer carries out communications while moving over the inter-connected networks, the computer program product comprising:

a first computer readable program code for causing said computer to store a current location address acquired by, the mobile computer at a visited site network outside a home network of the mobile computer, and a home address assigned to the mobile computer at the home network, in correspondence to a host name of the mobile computer; and

a second computer readable program code for causing said computer to update the current location address stored by the first computer readable program code according to a notification regarding the current location address received directly from the mobile computer, and to respond to an inquiry for the current location address of the mobile computer and an inquiry for the home address of the mobile computer received directly from a correspondent computer of the mobile computer.

15. A computer program product for causing a computer to function as a correspondent computer device for carrying out communications with a mobile computer which is capable of carrying out communications while moving over inter-connected networks, the computer program product comprising:

a first computer readable program code for causing said computer to store cryptosystem parameter information necessary in forming a tunnel for transferring an encapsulated packet with respect to the mobile computer; and

a second computer readable program code for causing said computer to manage source addresses of an outer packet and an inner packet of the encapsulated packet received directly from the mobile computer respectively as a current location address acquired by the mobile computer at a visited site network outside a home network of the mobile computer and a home address assigned to the mobile computer at the home network, and to update the current location address used as a termination endpoint address of the tunnel in the cryptosystem parameter information stored by the first computer readable program code into a new current location address, when a change of the current location address to the new current location address is notified directly from the mobile computer.

16. A computer program product for causing a computer to function as a correspondent computer device for carrying out communications with a mobile computer which is capable of carrying out communications while moving over inter-connected networks, the computer program product comprising:

a first computer readable program code for causing said computer to make an inquiry about the mobile computer directly to a computer management device that manages a current location address acquired by the mobile computer at a visited site network outside a home network of the mobile computer and a home address assigned to the mobile computer at the home network, before initiating a packet transmission to the mobile computer; and

a second computer readable program code for causing said computer to transmit a packet directly to the mobile computer located at the visited site network, by encapsulating an inner packet haying the home address as a destination address, within an outer packet having the current location address as a destination address, when the current location address and the home address are obtained from the computer management device in response to the inquiry made by the first computer readable program code.