【作者】 欧迎丰；

【导师】 李仁发；

【作者基本信息】 湖南大学 ， 计算机应用技术， 2004， 硕士

【摘要】 近年来，远程办公、移动计算的应用需求不断增长。在无线应用中，当移动主机在不同的子网之间移动时，为了保证正常通信，必须进行切换。移动IP切换已成为影响无线网络性能的关键问题，移动IP的切换机制研究已成为计算机网络的重要研究内容之一。 本文首先对移动IP的切换机制，切换的移动检测机制及其所采用的各种方法进行了较深入的分析；阐述了注册过程中移动主机与各种代理之间接收或产生注册消息的交互过程，并对移动IPv6协议体系与切换机制及其存在的问题进行了详细分析。将现有各种快速切换方案归类为层次移动管理、蜂窝IP和HAWAII、结合链路层信息的切换方案等，并对它们进行了综合的分析和评价。在平滑切换方面，讨论了当前普遍使用的单播转发和组播转发两种分组缓存转发机制。基于移动IPv4的层次移动管理结构映射到移动IPv6体系结构上，提出了分级移动IPv6结构和区域移动IPv6结构两种基于IPv6改进方案。 检测时延是切换时延中最主要的部分，它的产生是因为移动主机只能被动的进行移动检测。在现有的基础上，提出并实现了一种自适应主动预测邻居单播移动IP切换方案——AIPNU．MIP(Adaptive Initiative Predictire Neighbour Unicast Mobile IP)，采用自适应主动预测算法，根据移动主机活动和网络状况等情况进行综合智能预测，并通过反馈结果对算法进行动态调整，方案中充分考虑了乒乓效应等特殊情况。此外AIPNU．MIP还结合层次移动管理方法，减小注册时延，同时采用预测邻居单播，实现了快速平滑的切换。 最后，在Linux+NS的仿真平台下，构建网络实验环境，就标准移动IP及其典型的改进方案——层次管理方案和AIPNU．MIP进行了对比试验。实验结果表明：AIPNU．MIP与其它机制相比，能够大大地减少切换时延和切换的次数，保证分组的按时到达，提高系统的切换性能，保证系统的QoS。更多还原

【Abstract】 In recent years, the applications of remote office and mobile computing keep increasing. In wireless environment, The Mobile Host must perform handoff to keep the connections when it moves between different sub networks. The handoff has been the key factor of the wirless system and the studies on the Mobile IP handoff has become one of the important researching fields of the computer wireless network.Firstly, the paper make analysis in depth of the Mobile IP handoff scheme, the motion detection scheme as well as its different methods adopted. The interaction processes of receiving and affording the register messages between the host and the agents are explained in detail. Meanwhile the Mobile IPv6 architectrue and it’s handoff scheme are discussed and the existing problems are exposed. The paper classifies various fast handoff shcemes into hierarchical mobility management scheme, Celluar IP and HAWAII,, the handoff scheme combined with information of data link layer etc, according to comprehensive analysision and evaluation. In the way of smooth handoff, two systems of unicast forwarding and multicast forwarding which are widely used as packets cache and forwarding schemes of handoff are discussed. Based on the theory that mobile IPv4 of hierarchical mobility management mapped onto the Mobile IPv6 architecture, two improving schemes of hierarchical Mobile IPv6 and Regional Mobile IPv6 are presented.The handoff latency is the main section of the latency of the motion detection, which is caused by the fact that the host has to passively perform the motion detection. The paper presents and accomplishes the AIPNU.MIP (Adaptive Initiative Predictive Neighbor unicast Mobile IP). It adopts the adaptive initiative predictive algorism, intellectively predicts according to the network conditions and the movement of the Mobile Host, and adjusts itself corresponding to feedbacks. The special situation of PingPang (Table-tennis) effect is also fully considered. Besides, Combined with the hierarchical mobility management scheme, AIPNU.MIP also reduces the latency of registration and by adopting the predictive neighbor unicast, a fast and smooth handoff is achieved.Eventually, the paper demonstrates a contrast experiment in terms of emulating standard Mobile IP hierarchical mobility management MIP and AIPNU.MIP in the network testing conditions established on the Linux + NS simulation platform. Theresults indicate that contrasting with the standard Mobile IP and hierarchical mobility management MIP, AIPNU.MIP reduces the handoff latency and the counters of handoff greatly, guarantees the packet’s arriving in time, increases the handoff performance of the system, and maintains a better QoS.更多还原