COMMUNICATION METHOD, MOBILE AGENT DEVICE, AND HOME AGENT DEVICE

• US 20090092095A1
• Filed: 11/16/2006
• Published: 04/09/2009
• Est. Priority Date: 11/16/2005
• Status: Active Grant

• Current Assignee: NTTPC Communications, Inc.
• Original Assignee: NTTPC Communications, Inc.
• Inventors: Hata, Hiroaki, Futana, Nobuaki, Ishikawa, Hajime
• Granted Patent: US 8,717,941 B2
• Time in Patent Office: Days
• US Class Current: 370/331
• CPC Class Codes: H04L 61/103 across network layers, e.g. resolution of network layer into physical layer addresses or address resolution protocol [ARP]
• CPC Class Codes: H04L 61/59 using proxies for addressing
• CPC Class Codes: H04W 60/00 Affiliation to network, e.g. registration; Terminating affiliation with the network, e.g. de-registration
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]
• CPC Class Codes: H04W 8/06 Registration at serving network Location Register, VLR or user mobility server
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]
• CPC Class Codes: H04W 88/182 Network node acting on behalf of an other network entity, e.g. proxy

Abstract

In a communication system including a MN, a MFA connected to the MN, and a HA connected to a home network of the MN, the HA holds a layer 3 address of the HA and a source layer 3 address of a registration request by associating them with each other. The MFA transmits a layer 2 frame from the MN to the HA by encapsulating it. The HA decapsulates the frame to transmit it to the home network. When the HA receives a layer 2 frame from the home network, the HA checks that the destination layer 3 address is registered, and encapsulates the layer 2 frame to transmit it to a source layer 3 address of the registration request that is registered being associated with the destination layer 3 address. The MFA decapsulate the encapsulated layer 2 frame to transmit the layer 2 frame to the MN.

Claims

1. A communication method in a communication system including a user terminal, a mobile agent apparatus connected to the user terminal, and a home agent apparatus connected to a home network of the user terminal, wherein,

based on a registration request transmitted by the mobile agent apparatus, the home agent apparatus registers a layer 3 address of the user terminal and a source layer 3 address of the registration request in an address correspondence table by associating them with each other, and the mobile agent apparatus holds the layer 3 address of the user terminal;

when the user terminal transmits a packet to a communication partner terminal, the mobile agent apparatus receives a layer 2 frame from the user terminal, and if a source layer 3 address in a layer 3 header in the layer 2 frame is registered, the mobile agent apparatus encapsulates the received layer 2 frame to transmit it to the home agent apparatus;

the home agent apparatus decapsulates the encapsulated layer 2 frame to extract the layer 2 frame, and transmits the layer 2 frame to the home network, and a router that accommodates the home network transfers a packet to the communication partner terminal;

when the communication partner terminal transmits a packet to the user terminal, the home agent apparatus receives a layer 2 frame from the home network, checks that a destination layer 3 address in a layer 3 header in the layer 2 frame is registered in the address correspondence table, and encapsulates the layer 2 frame to transmit it to a source layer 3 address of the registration request that is registered being associated with the destination layer 3 address; and

the mobile agent apparatus receives the encapsulated layer 2 frame, decapsulates it to extract the layer 2 frame and transmit the layer 2 frame to the user terminal.

3. The communication method as claimed in claim 1 or 2, wherein,

the home agent apparatus holds identification information of a second mobile agent apparatus that should not be connected to the home agent apparatus and an address of a second home agent apparatus to which the second mobile agent apparatus should connect in an address correspondence table by associating them with each other;

and

when the home agent apparatus receives a registration request transmitted from the second mobile agent apparatus, the home agent apparatus refers to the address correspondence table to transmit a redirect response including an address of the second home agent apparatus to the second mobile agent apparatus.

2. A communication method in a communication system including a user terminal, a mobile agent apparatus connected to the user terminal, and a home agent apparatus connected to a home network of the user terminal, wherein,

based on a registration request transmitted from the mobile agent apparatus, the home agent apparatus registers a layer 3 address of the user terminal and a source layer 3 address of the registration request in an address correspondence table by associating them with each other, and the mobile agent apparatus holds the layer 3 address of the user terminal;

when the user terminal transmits a packet to a communication partner terminal, the mobile agent apparatus receives a layer 2 frame from the user terminal, and if a source layer 3 address in a layer 3 header in the layer 2 frame is registered, the mobile agent apparatus encapsulates a packet obtained by deleting a layer 2 header of the received layer 2 frame to transmit it to the home agent apparatus;

the home agent apparatus decapsulates the encapsulated packet to extract the packet, and transfer the packet based on a layer 3 header;

when the communication partner terminal transmits a packet to the user terminal, the home agent apparatus receives the packet, checks that a destination layer 3 address in a layer 3 header of the packet is registered in the address correspondence table, and encapsulates the packet to transmit it to a source layer 3 address of the registration request that is registered being associated with the destination layer 3 address; and

the mobile agent apparatus receives the encapsulated packet, decapsulates it to extract the packet and transmit the packet to the user terminal.

4. The communication method as claimed in claim 2, wherein,

when the mobile agent apparatus receives an ARP request from the user terminal, if the mobile agent apparatus checks that a source layer 3 address of the ARP request is registered in the mobile agent apparatus, the mobile agent apparatus transmits an own MAC address to the user terminal as a response to the ARP request.

5. A mobile agent apparatus used in a communication system including a user terminal, the mobile agent apparatus connected to the user terminal, and a home agent apparatus connected to a home network of the user terminal, comprising;

storing means configured to hold a layer 3 address of the user terminal;

means configured to receive a layer 2 frame from the user terminal, and if a source layer 3 address in a layer 3 header in the layer 2 frame is registered in the storing means, encapsulate the received layer 2 frame and transmit it to the home agent apparatus; and

means configured to receive an encapsulated layer 2 frame, decapsulate it to extract a layer 2 frame and transmit the layer 2 frame to the user terminal.

6. A mobile agent apparatus used in a communication system including a user terminal, the mobile agent apparatus connected to the user terminal, and a home agent apparatus connected to a home network of the user terminal, comprising;

storing means configured to hold a layer 3 address of the user terminal;

means configured to receive a layer 2 frame from the user terminal, and if a source layer 3 address in a layer 3 header in the layer 2 frame is registered in the storing means, encapsulate a packet obtained by deleting a layer 2 header of the received layer 2 frame to transmit it to the home agent apparatus; and

means configured to receive an encapsulated packet from the home agent apparatus, decapsulate it to extract a packet and transmit the packet to the user terminal.

7. The mobile agent apparatus as claimed in claim 6, wherein, when the mobile agent apparatus receives an ARP request from the user terminal, if a source layer 3 address of the ARP request is registered in the storing means, and the mobile agent apparatus transmits an own MAC address to the user terminal as a response to the ARP request.

8. A home agent apparatus in a communication system including a user terminal, a mobile agent apparatus connected to the user terminal, and the home agent apparatus connected to a home network of the user terminal, wherein,

means configured to, based on a registration request transmitted by the mobile agent apparatus, register a layer 3 address of the user terminal and a source layer 3 address of the registration request in an address correspondence table by associating them with each other;

means configured to receive an encapsulated layer 2 frame including a packet addressed to a communication partner terminal from the mobile agent apparatus, decapsulate the encapsulated layer 2 frame to extract the layer 2 frame, and transmit the layer 2 frame to a router in the home network; and

means configured to receive a layer 2 frame including a packet from the home network, and, if a destination layer 3 address in a layer 3 header in the layer 2 frame is registered in the address correspondence table, encapsulate the layer 2 frame to transmit it to a source layer 3 address of the registration request that is registered being associated with the destination layer 3 address.

10. The home agent apparatus as claimed in claim 8 or 9, wherein,

the home agent apparatus holds identification information of a second mobile agent apparatus that should not be connected to the home agent apparatus and an address of a second home agent apparatus to which the second mobile agent apparatus should connect in an address correspondence table by associating them with each other;

and

when the home agent apparatus receives a registration request transmitted from the second mobile agent apparatus, the home agent apparatus refers to the address correspondence table to transmit a redirect response including an address of the second home agent apparatus to the second mobile agent apparatus.

9. A home agent apparatus in a communication system including a user terminal, a mobile agent apparatus connected to the user terminal, and the home agent apparatus connected to a home network of the user terminal, wherein,

means configured to, based on a registration request transmitted by the mobile agent apparatus, register a layer 3 address of the user terminal and a source layer 3 address of the registration request in an address correspondence table by associating them with each other;

means configured to decapsulate an encapsulated packet addressed to a communication partner terminal to extract the packet, and transfer the packet based on a layer 3 header to the communication partner terminal; and

means configured to check that a destination layer 3 address in a layer 3 header of a received packet is registered in the address correspondence table, and encapsulate the packet to transmit it to a source layer 3 address of the registration request that is registered being associated with the destination layer 3 address.