Research On DAD Check Based On MLD In HMIPv6

Mobile communication has been developed whip and spur as well as Internet. People are paying more and more attention on the amalgamation of Internet and mobile communication. The requirement of connecting on Internet anywhere is exigent. It is mobile-Internet that provide Internet service and make Internet mobile is appeal to people.IETF group promulgated a technology for the next generation Internet which is called MIPv6 with the prupose of mobile-Internet. The MIPv6 node would keep the communication on current link when the mobile node changes its position, which is the outstanding strongpoint of MIPv6. However we found that a large number of binding update messages would be produced in MIPv6, when the MN moves among different subnet for its fast handover. The long time handover latency, the lost of data packet, the decline and break off of communication quality, which are the result of the operation.IETF group promulgated Hierarchical Mobile IPv6 Mobility Management (HMIPv6) in which the mobility management is divided into Macro-mobility and Micro-mobility aim at the bugs of MIPv6. A new entity called mobility anchor point(MAP) is introduced in HMIPv6 based on MIPv6 with the purpose of reforming the mobility management of nodes. The Duplicate Address Detection(DAD) check on link care-of address(LCoA) and regional care-of address(RCoA) cost majority of IP layer handover time in HMIPv6 by the research and analysis. The paper brings forward a new DAD check scheme that which is based on Multicast Listener Discovery(MLD). Temporary multicast group would be set up for MN by the way of MLD in the new scheme. The advantage of the scheme is that the DAD check on IPv6 node and the normal message transfer and signal communication on link are synchronous. The latency of the temporary multicast group constitute is greadtly less than the DAD check. So the efficiency of DAD check on care-of address would be improved effective which is the innovation of the paper.A simulation for the scheme by NS-2 was operated under the practical situation. The performace analysis and the test result of NS-2 simulation has shown that the handover arithmetic is optimized, handover efficiency has been enhanced and the mobility management has been improved.