Patent ID: 7567534

Claim:
A mobile host comprising: a communication status detection unit configured to detect that a communication status in a network layer is in a Dormant state, said communication status detection unit being further configured to transmit a Dormant state notification to a data link layer connection establishment notification unit; the data link layer connection establishment notification unit configured to notify the network layer that a connection to a link in a data link layer has been established, upon receipt of the Dormant state notification from the communication status detection unit that the mobile host is in the Dormant state; and a network layer movement detection unit configured to detect a default router, triggered by notification from said data link layer connection establishment notification unit; and a router information requesting unit configured to transmit a Router Solicitation which requests transmission of router advertisement information to the access router existing on the access link to which said mobile host is connected, in response to the notification by said data link layer connection establishment notification unit, wherein said network layer movement detection unit is configured to detect a default router, based on the router advertisement information returned from said access router, in response to said Router Solicitation.