This document proposes Access Router (AR) based movement detection and Care-of Address (CoA) configuration for fast handover in Mobile IPv6. An Active Access Router (AcAR) which will serve a Mobile Node (MN) performs movement detection, formulates a new CoA of the MN and does Duplicate Address Detection (DAD) on behalf of the MN. After confirming the uniqueness of the new CoA, the AcAR sends it through a RA message. Since an AcAR can quickly determine the L3 movement by the comparison between neighbor caches and L2 information of a MN, a MN does not have to wait to receive RA messages from ARs. Thus, the movement detection delay is reduced. Since DAD is performed by an AcAR in advance, a MN does not have to do normal DAD and it can use the new CoA for its interface directly.