Handoff method and agent apparatus

Claim 2

The handoff method according to Claim 1, characterized in that in said double regional registration step, said mobile terminal equipment is registered with a home agent (3), and said home agent performs said IP packet determination step, said bicasting and buffering step, and said transferring step.

Claim 3

The handoff method according to Claim 2, characterized in that said home agent determines whether or not an IP packet destined for said mobile terminal equipment is of real-time traffic based on information on a header of the IP packet.

Claim 4

The handoff method according to Claim 2 to 3, characterized in that said home agent determines whether or not an IP packet destined for said mobile terminal equipment is of real-time traffic based on information on an upper layer, which is placed in a payload of the IP packet.

Claim 5

The handoff method according to any of Claims 1 to 4, characterized in that in said double regional registration step, said mobile terminal equipment is registered with a gateway foreign agent (21), and said gateway foreign agent performs said IP packet determination step, said bicasting and buffering step, and said transferring step.

Claim 6

The handoff method according to Claim 5, characterized in that said gateway foreign agent determines whether or not an IP packet destined for said mobile terminal equipment is of real-time traffic based on information on a header of the IP packet.

Claim 7

The handoff method according to Claim 5, characterized in that said gateway foreign agent determines whether or not an IP packet destined for said mobile terminal equipment is of real-time traffic based on information on an upper layer, which is placed in a payload of the IP packet.

Claim 8

The handoff method according to any one of Claims 1 to 7, characterized in that said mobile IP network is a mobile phone network in accordance with Radio Access Network standards which can perform a mobile IP procedure, said mobile terminal equipment is a mobile phone (83), and each of said new and the previous foreign agents is a radio network control unit (81-1 or 81-2) that can give and receive an authority to control said mobile phone, as a handoff, according to an SRNC relocation procedure.

Claim 9

A handoff method of performing a handoff when mobile terminal equipment (2) is moving from a previous foreign agent (42-1) to a new foreign agent (42-2) in a mobile IP network (1), characterized in that said method comprises the steps of: when starting a handoff, additionally performing a regional registration of said mobile terminal equipment with a home agent so as to doubly register said mobile terminal equipment so that said mobile terminal equipment is associated with both said previous foreign agent and said new foreign agent; allowing said home agent to determine whether or not an IP packet destined for said mobile terminal equipment is of real-time traffic when said mobile terminal equipment is doubly registered; allowing said home agent to bicast the IP packet to both said previous foreign agent and said new foreign agent if the IP packet is of real-time traffic, and transferring the IP packet to said previous foreign agent if the IP packet is of non-real-time traffic; allowing said previous foreign agent to buffer the IP packet of non-real-time traffic transferred from said home agent therein; when the handoff is completed, if IP packets of non-real-time traffic are buffered in said previous foreign agent, allowing said previous foreign agent to transfer the buffered IP packets of non-real-time traffic to said new foreign agent; and when the handoff is completed, updating the regional registration associated with said previous foreign agent so that said mobile terminal equipment is associated only with said new foreign agent.

Claim 10

An agent apparatus (3) for transferring IP packets to a new foreign agent (5-2) in a mobile IP network (1), to which mobile terminal equipment (2) is moving, characterized in that said apparatus comprises: a means for, upon receiving an IP packet destined for said mobile terminal equipment when said mobile terminal equipment is doubly registered during a handoff, determining whether or not the IP packet is of real-time traffic; a means for bicasting the IP packet to both said previous foreign agent and said new foreign agent if the IP packet is of real-time traffic, and for buffering the IP packet if the IP packet is of non-real-time traffic; a means for, when the handoff has been completed and IP packets of non-real-time traffic are buffered, transferring the buffered IP packets of non-real-time traffic to said new foreign agent.