Routing Research Based On IPv6

With the rapid development of Internet and mobile communication technology, portable mobile devices such as mobile phones and laptops have been used widely. More and more people want to access Internet in any place and keep communication continuous while moving. So IETF group brings forward Mobile IPv6 protocol. But when Mobile node enters a new subnet, the handover procedures may lead long delay and high packets losses, the correspondence will be interrupted and the Qos will be descended as well. How to retain the continuity and reduce delay to ensure the real-time applications such as Voice over IP becomes the most important work in Mobile IPv6 research.In order to optimize the handover delay in standard Mobile IPv6, IETF group brings out several improved handover protocol.Fast handover for Mobile IPv6 (FMIPv6) registers in advance by obtaining the information of the new subnet, and keep the communication continuous after finishing the handover. In this way, the handover delay in standard Mobile IPv6 can be decreased. Hierarchical Mobile IPv6 (HMIPv6) divide the whole network into many fields, each field will be managed by a new entity called mobility anchor point (MAP). When the mobile node moves inside a field, the MAP will transmit the data packets with correspondent nodes instead of home agent. So the number of binding up messages between MN and CN will be decreased and the handover delay will be improved. Fast handover for hierarchical MIPv6 technology (FHMIPv6) integrates FMIPv6 and HMIPv6; arrange fast handover in hierarchical Mobile IPv6 mobility management and decreases the handover delay even more.By research of FHMIPv6, the procedure of duplicated address detection (DAD) badly decreases the performance of handover, so a new technology named multicast-fast handover for hierarchical MIPv6 (M-FHMIPv6) has been putted forward based on IPv6 multicast. When the mobile nodes has detected L2 trigger and knows that it will enter a new subnet, so it switches to multicast mode and a multicast group will be set up. CN, PAR and NAR will join it. CN becomes the multicast source and keep sends data packets to MN until the handover has been finished.The theoretical analysis shows that although M-FHMIPv6 needs to build multicast group in handover procedure, but can effectively reduce handover delay caused by DAD and information exchange. Finally, simulator in NS2 further proved that M-FHMIPv6 can reduce delay and smooth handover process, achieve the desired results.