Patent ID: 8077648

Claim:
A method for mobility management used in an IP-based network system, which contains a plurality of access routers (AR), location managers (LM) and routing managers (RM), through which a mobile node (MN) transmits and receives information, the method comprising the steps of: determining whether or not the mobile node is active; monitoring the mobile node via a visited routing manager (VRM) where the mobile node is currently located if the mobile node is active; first determining whether or not the mobile node is moving out of a connectivity range from one of the plurality of access routers which is currently communicating with the mobile node, wherein the plurality of access routers is grouped into regions, each region having two or more access routers which select the same visited routing manager for the same mobile node; second determining whether the mobile node is moving out of a control range of the visited routing manager (VRM) which is currently managing the mobility of the mobile node; transferring context which the current access router holds to a new access router in a case where it is determined at said first and second determining steps that the mobile node is moving out of the connectivity range from the access router but is still within the control range of the current visited routing manager; and transferring context which the current visited routing manager holds to a new visited routing manager under an assist by a home routing manager (HRM) in a case where it is determined at said first and second determining steps that the mobile node is moving out of the connectivity range from the access router and the control range of the current visited routing manager.