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

摘要： HMIPv6 协议作为MIPv6协议的改进，有效地解决了切换过程中的切换时延问题，但仍未达到无缝切换以满足特定网络服务的要求，关键原因是对LCoA和RCoA的DAD操作占据了主要切换时延，严重影响了切换效率。利用链路层切换辅助网络层切换，并对转交地址进行有效管理分配的新策略，能够避免切换过程中的DAD操作。通过仿真证明，这种策略能够减少切换时延，有效提高HMIPv6切换性能。

关键词: 层次移动IPv6, 重复地址检测, 地址表, 切换时延