【作者】 陈琳；

【导师】 宋健；

【作者基本信息】 兰州理工大学 ， 通信与信息系统， 2008， 硕士

【摘要】 在Internet迅猛发展的今天,移动通信也得到了飞速地发展,Internet和移动通信的融合也越来越受到人们的关注,人们在任何地方能够接入Internet的需求也越来越迫切,为移动通信用户提供Internet服务和让Internet移动起来对用户是很有现实意义和吸引力的,这就是移动互联网。为了实现移动互联网,因特网工程任务(IETF)组提出了针对下一代互联网的移动IPv6(MIPv6)技术。MIPv6的突出优点就是移动节点改变其位置的过程中,该MIPv6节点仍然会保持现有链路的通信,并且其IP地址不变。但是通过研究我们发现标准MIPv6中,当移动节点在不同子网间快速切换时,会产生大量的绑定更新报文,从而导致长时间的切换时延和数据包的丢失,引起通信质量的下降和中断。针对标准MIPv6中的缺陷,IETF提出了分级移动IPv6(HMIPv6)管理方案,将移动分为宏移动和微移动进行管理。HMIPv6在标准MIPv6的基础上引入了移动锚点(MAP)来改善节点的移动性管理。通过分析可以发现在HMIPv6中,对链路转交地址和区域转交地址的重复检测操作做需要的时间占IP层切换的绝大部分时间,本文针对此提出了一种基于组播侦听者发现协议(MLD)的重复地址检测(DAD)方案,该方案运用MLD为移动节点建立临时组播组的方法,可以使IPv6节点在进行DAD检测的同时,仍然可以进行正常的链路上的报文传递和信令通信,而进行MLD建立组播组过程所带来的延时相对于传统的DAD检测则要小得多,从而可以有效地解决转交地址重复检测操作的问题。这也正是本文的创新之处。结合实际情况,运用NS-2对该方案进行了仿真,性能分析与测试结果表明该方案优化了切换算法,提高了切换效率,改善了移动性管理。更多还原

【Abstract】 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.更多还原