Handoff method and agent apparatus

摘要

In accordance with a handoff method, when a handoff of mobile terminal equipment (2) from a previous foreign agent (5-1) to a new foreign agent (5-2) is detected, the mobile terminal equipment is doubly registered with either a home agent (3) or a gateway foreign agent (21) so that the mobile terminal equipment is associated with both the previous foreign agent and the new foreign agent. During the handoff, either the home agent or the gateway foreign agent determines whether or not an IP packet destined for the mobile terminal equipment is of real-time traffic, and then bicasts the IP packet to both the previous foreign agent and the new foreign agent if the IP packet is of real-time traffic, and buffers the IP packet otherwise. When the handoff is completed, the regional registration with either the home agent or the gateway foreign agent is updated so that the mobile terminal equipment is associated only with the new foreign agent. Either the home agent or the gateway foreign agent then transfers IP packets of non-real-time traffic buffered therein to the new foreign agent.