Patent ID: 8514805

Claim:
A method of performing handover in a mobile node from a current Point of Attachment (PoA) to a new PoA, comprising: in a handover function layer, receiving subnet information from an information server for the new PoA before a handover in a lower layer is initiated; in the handover function layer, comparing subnet information for the current PoA with the subnet information for the new PoA; in the handover function layer, determining a layer selected from a plurality of layers in which a handover is performed, according to whether the subnet information for the current PoA matches the subnet information for the new PoA and sending a message for the handover to the determined layer before initiating a handover in the lower layer; and performing the handover in the determined layer, wherein performing of the handover in an upper layer comprises: transmitting an event message to the upper layer, having an event name field indicating that there is a change of subnet via a layer 3 (L3) handover to be performed and an event type field indicating that a state change is to occur in the L3 layer; and performing the layer 3 (L3) handover in the upper layer.