Handover method and mobile terminal and home agent used in the method

A handover method for a mobile node moving between at least two networks each supporting a unique and different IP version as a protocol of the mobile node, comprising the steps of:

• when the mobile node performs handover from a first access router in a network currently connecting before handover to a second access router in another network as a handover target, and when an IP version supported by the network as the handover target and an IP version supported by the network before handover are different,
• a step where the mobile node transmits a first message to a home agent via the first access router, the first message including an allocation solicitation request for a home address in the network as the handover target, and transmits a second message via the second access router, the second message including an address acquisition request;
• and
• a step where the home agent transmits a third message to the mobile node based on the allocation solicitation request for a home address included in the first message, the third message including a home address in the network as the handover target, and transmits a fourth message to the mobile node based on the address acquisition request, the fourth message including the home address.

A mobile node performing handover between at least two networks each supporting a unique and different IP version as a protocol of the mobile node, the mobile node comprising:

• when the mobile node performs handover from a first access router in a network currently connecting before handover to a second access router in another network as a handover target,
• a determination unit that determines as to whether an IP version supported by the network as the handover target and an IP version supported by the network before handover are different or not;
• a message generation unit that, when it is determined that the IP versions are different, generates a first message including an allocation solicitation request for a home address in the handover target and a second message including an address acquisition request;
• a transmission unit that transmits the generated first message to a home agent via the first access router and transmits the second message via the second access router;
• and
• a reception unit that receives, based on the allocation solicitation request for a home address included in the first message, a third message including a home address in the network as the handover target transmitted from the home agent, and receives a fourth message including the home address transmitted by the home agent based on the address acquisition request included in the second message.

A home agent of a mobile node, the mobile node performing handover between at least two networks supporting a unique and a different IP version as a protocol of the mobile node, the home agent comprising:

• when the mobile node performs handover from a first access router in a network currently connecting before handover to a second access router in another network as a handover target, and when an IP version supported by the network as the handover target and an IP version supported by the network before handover are different,
• a reception unit that receives, from the mobile node, a first message including an allocation solicitation request for a home address in the network as the handover target and a second message including an address acquisition request;
• a message generation unit that generates a third message including a home address in the handover target based on the allocation solicitation request for a home address in the first message and a fourth message including the home address based on the address acquisition request;
• and
• a transmission unit that transmits the generated third and fourth messages to the mobile node.