【作者】 王玉辉；

【导师】 黄传河；

【作者基本信息】 武汉大学 ， 计算机系统结构， 2004， 硕士

【摘要】 下一代移动通信系统将是全IP移动通信系统,其移动性管理策略由移动PPP协议和移动IP协议这两个重要的支撑协议组成。而如何将Diameter技术和移动性管理技术融合实现AAA(Authentication、Authorization、Accounting)是无线IP网络中最重要和最具挑战性的问题之一。 各种不同网络的融合以及互联网本身的飞速发展,迫切需要新一代的基于IP技术的AAA。IETF AAA工作组提出的Diameter协议族将取代RADIUS成为新的AAA协议。IETF提出的移动IP协议具有广泛的应用前景,有望取代现有移动通信系统中的各种移动性管理协议,解决未来移动通信系统中的移动性管理问题。但移动IP技术也存在一些固有的缺陷,如切换中不能保证通信业务的服务质量、位置注册时延过长等。目前的研究倾向于采用一种层次型的移动性管理方法来解决这些问题,即用移动IP来支持宏移动(macro-mobility),而采用更优化的微移动(micro-mobility)协议来进行本地移动性管理。 本文对移动性管理的基本原理、Diameter协议以及现有的移动性管理协议进行了详细的分析,提出了在使用移动IP解决无线IP网络中的移动性管理问题时,如何利用更为优化的微移动性管理协议来处理本地移动性等问题;提出了分别针对移动IP和移动PPP协议的移动性管理实现策略;重点提出了一种全新的、融合Diameter技术的移动性管理方案。该方案遵从层次型移动性管理的思想,采用处于2+层的移动PPP协议处理本地移动性,移动PPP为移动IP屏蔽链路层的切换,使移动IP很容易实现快速平滑的切换,同时移动PPP完成Diameter协议实现AAA的适配功能,使得整个方案在切换过程中不存在丢失数据包的现象,平滑认证计费授权,获得很小的切换时延。最后,基于所提出的方案构建实验平台,对方案进行模拟,对系统性能进行测试。试验平台结果证实了所提方案的可行性。更多还原

【Abstract】 It is the all-IP mobile communication system that will be the next generation of mobile communication system, whose mobility management is consisted of two supporting protocols :mobile PPP and mobile IP; meanwhile, mobility management is recognized as one of the most important issues and challenging in wireless IP networks.Considering the integration of different types of network and the rapid development of Internet, a new technology based on IP is urgently needed. Therefore, IETF advanced Diameter protocol which will replace Radius and become the new AAA protocol. Mobile IP, which was proposed by IETF, with its far and wide prospect in application is expected to be a promising solution in the future mobile communication systems and consequently a replacement of the various mobility management protocols in the existing mobile communication systems nowadays. But, mobile IP technology has some built-in weaknesses. For instance, it fails to guarantee the QoS (Quality of Service) of ongoing sessions in handoffs; it may cause unacceptable latency in location registration. And present researches are inclined to adopt a hierarchical mobility management approach to solve these problems, i.e. making use of the Mobile IP to support macro-mobility, and the optimized micro-mobility protocols to manage local area mobility.Based on the research existing outcomes, this paper promotes an approach of mobility management in an all-IP cellular mobile communication system platform. The two critical supporting protocols are included in this approach: one is the special MPPP (Mobile Point-to-Point Protocol) protocol, and the other is the Mobile IP protocol. Diameter is implemented based on the two protocols. Besides conforming to the standards already existed, both of the protocols have been added to some features particularly for the wireless IP networks. The function of mobility management is introduced into the MPPP protocol, which can support PPP handoffs of mobile subscribers. By using the scheme of tunnel, the MPPP protocol provides soft handoff in Data Link Layer and significantly supports local area mobility. Backed up by the MPPP protocol, the Mobile IP protocol can offer fast and smooth handoff, which applies the concept of post-registration handoff and leads to no packet loss and low latency in the handoffs. More details on the implementation and performance simulation are elaborated in my thesis. It has been proved by the sufficient results of simulation that this approach is practicable, especially for its contribution in fastness and smoothness of handoff, which is considered to be an innovation and indicates the benefit of Diameter.更多还原