基于组播绑定的注册方法研究

【作者】 何华江；

【导师】 王晓斌；

【作者基本信息】 电子科技大学 ， 计算机软件与理论， 2005， 硕士

【摘要】 随着移动通信技术的发展,互联网上已经出现了越来越多的移动终端,来自EMC 的统计数据显示,截止2003 年底,全球移动用户已达到13.54 亿。传统采用电路交换的无线网络将逐步被改造为以IP 分组交换为基础的无线网络,这种情况下,移动IP 将变得与无线网络同样重要, 特别是在将来3G 网络的建设中, 移动IPv6不仅将成为移动运营商必须要做出选择的一项重要技术,还将成为能够使3G 网络和热点地区的蓝牙或Wi-Fi ( 802.11b)之间实现无缝漫游的一种基本技术。但是, 根据现有的IETF 移动IPv6 规范( RFC3775), 当移动节点接入外地网络后,首先要向家乡代理注册,在收到家乡代理的绑定确认后才开始向通信节点注册。而且,移动节点需要依次向每个通信节点进行注册。这样,当移动节点移动比较频繁或者离家乡代理和通信节点较远时,将会产生大量的注册报文,从而引起较大的切换时延,严重的包丢失和通信吞吐量下降。如何提高移动节点的切换性能成为MIPv6 发展的关键。许多大公司和科研机构在相关方面展开了大量的研究,获得了许多成果,形成了一些对MIPv6扩充和改进的草案, 包括快速切换, 分层结构, DAD 优化等, 用以改进移动节点切换涉及的移动检测、地址配置和绑定更新。然而,当通信节点较多时,由于移动节点是依次向通信节点注册的,后面的通信节点就会产生很大的注册时延,关于这一点,并没有相关草案涉及。本文利用组播技术,改进移动节点切换后向通信节点注册的过程,使得移动节点无须再依次向通信节点注册,而是使用一个临时的对应所有通信节点的组播地址,把绑定更新报文发送到该组播地址对应的组播组,一次完成对所有通信节点的注册。本文详细阐述了其原理、实现方法和性能。并运用OMNeT++仿真软件, 分别对移动IPv6、分层结构移动IPv6 和利用组播绑定的移动IPv6 中的切换场景进行了仿真, 并对仿真结果进行了分析和比较。更多还原

【Abstract】 The mobile communications is blasting, and there are more andmore mobile terminals nowadays. According to EMC, the number ofmobile users has reached 1,354,000,000 in 2003. The wirelessnetworks based on packet-switch will replace that which based oncircuit-switch, so mobile IP is going to be the same important aswireless networks. In future 3G networks, mobile IPv6 is the mostcritical technology to all carriers, and is the essential elements forseamless handovers between 3G, Bluetooth and Wi-Fi.But, according to IETF RFC3775, When a mobile node accessesthe foreign network, it must register it’s new CoA to the Home Agent.After receiving the BAck from the HA, the Mobile Node thenregisters it’s new CoA to all Correspondent Nodes in turn. So, whilethe MN moves frequently or it leaves far away from the HA and CNs,there will be a lot of registering messages. The messages can cause along latency that leads to significant packet drop and throughputreduction. It’s the key to MIPv6 that how to improve the performanceof handovers. And,some enterprises and institutes began to carry outresearches on this topic. Several drafts about it are released fromIETF, such as Fast Handovers for Mobile IPv6, Hierarchical MobileIPv6 mobility management (HMIPv6), MLD-DAD and so on.However, there’s no draft talk about reducing the latency between theMN an CNs, especially the number of CNs is large.In this paper, a new registration process which makes use ofmulticast is introduced. The new process frees the MN fromregistering to each CN. The MN then can send the BUs to a tempmulticast address representes all of CNs, thus only once the MN needto register to CNs .The principle, implementation and performancehave been analyzed in this paper. And, using OMNeT++, thesimulations for MIPv6,HMIPv6 and M-MIPv6 are performed, theresults are also analysised.更多还原