关键词: 层次移动IPv6, 重复地址检测, 地址表, 切换时延

Abstract: The HMIPv6 protocol has been proposed as an improved technology of MIPv6 which has solved the problem of handover latency efficiently.But it didn’t work as well as seamless handover that some special network services need.It’s mainly because that the DAD checks of LCoA and RCoA occupied a majority of handover latency，which affects the handover performance badly.A policy of the link layer assists the network layer is proposed，and with the efficient address management，it can avoid DAD check during handover.It is proved in the simulation that the handover latency would be shortening，and the performance of HMIPv6 handover would be improved efficiently.

Key words: HMIPv6, Duplicate Address Detection（DAD）, address table, handover latency