Patent ID: 7916692

Claim:
A mobile communication system including a first mobile terminal, a current edge router to which the first mobile terminal is connected, and a first home agent for managing, as a group, a first care-of address when the first mobile terminal is connected to the current edge router and a first home address of the first mobile terminal, wherein the first mobile terminal transmits the first home address to the current edge router, when the first mobile terminal is connected to the current edge router, the current edge router manages the first home address of the first mobile terminal, and when the first mobile terminal connected to the current edge router communicates with a second mobile terminal, the current edge router manages a second care-of address of the second mobile terminal corresponding to a second home address, and upon being informed of the second home address by the second mobile terminal, transmits, to the first home agent, a CN information request command for requesting information of the second mobile terminal including the second care-of-address and the second home address of the second mobile terminal, the first home agent, upon receiving the CN information request command, transfers the CN information request command to a previous edge router; and when the previous edge router receives the CN information request command transferred from the first home agent, the previous edger router transmits a CN information request acknowledgement command including the second care-of address of the second mobile terminal managed corresponding to the first home address included in the CN information request command, to the current edge router, and, when the current edge router receives the CN information request acknowledgement command from the previous edge router including the second care-of address of the second mobile terminal, the current edge router issues a location registration request to the first home agent.