Abstract: In a network system including at least one mobility anchor point (MAP) for managing mobility of a mobile node (MN) and a plurality of routers connected to the at least one MAP in a hierarchical structure, the MAP sends a MAP option to at least one router located on a higher level than the MAP. When receiving the MAP option, the router located on the higher level sends an updated MAP option to neighboring routers, after incrementing a predetermined upward value comprised in the MAP option. MAPs distributed in the network system can deliver MAP options regardless of the hierarchical structure of routers, and hence the MN can maximize its location privacy. Because the MAP performs MAP domain announcement using a DOMAIN option, service use of routers outside the MAP domain can be limited, and the number of times that a MAP is changed can be reduced.