| Recent years, as the rapid development of Internet,people's work and lives are closer to it. The functions of the mobile device become abundance, the price is cheaper, and the portability is attractive. So everyone wants to access to Internet anytime and anywhere with a mobile device, to make work and life better.Mobile IPv6 is one part of IPv6, so it is borned with some advantages which other handover technologies don't have. However, cause mobile ipv6 is based on ipv6, it cannot be deployed on current network devices which only support IPv4, that make the researchs on it only can process with simulation or lab network environment. This situation restricts the development of mobile ipv6. From the technique of mobile ipv6 itself, there are something should be improved based on different network handoff environments.We analyze two familiar handoff environments: WLAN which based on 802.11b and CDMA 1x, and make mobile device can handoff between WLAN and CDMA with mobile ipv6 and Silkroad tunnel mechanism. We overcome many difficulties, such as CDMA doesn't support IPv6 and stop some types tunnel packages. We also make the mechanism suitable to GPRS and other cell networks. So, it's a feasible way for the combination of mobile ipv6 and cell networks.On the other side, for optimizing the handoff performance, we implement two ways: soft handoff and binding update simulcast. The test result shows that they improve the handoff performance obviously. We also bring forward a concept named AP pool for optimizing the handoff between WLANs.We build a mobile manage system to do and optimize handoff. Based on standard mobile ipv6 software,we implement the modules which correspond to specify network, that make the total system flexible and extensible. The mobile manage system is one part of CNGI project and has to be tested run on CNGI network. |
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