【作者】 李昭桦；

【导师】 张宏科；

【作者基本信息】 北京交通大学 ， 通信与信息系统， 2007， 硕士

【摘要】 随着无线通信技术的进步,移动互联网已经成为当今研究热点。笔记本等移动设备的普及让人们随时随地接入互联网的需求更加迫切,其中,部署在轮船、火车等交通工具上的作为一个整体进行移动的网络是研究重点之一。IETF发布了移动IPv4协议,提供了网络层的终端移动性支持。IETF的MIP4工作组提交了一份草案,提供了在配置转交地址模式下的移动网络(NetworkMobility,NEMO)支持。但是,外地代理转交地址模式下的移动网络还没有解决方案。为了区别其它移动网络,本文将“NEMO”称为移动子网。本文在采用MIP4工作组草案的消息格式定义和符号定义的基础上,扩展移动IPv4协议,提出了在外地代理转交地址模式下的IPv4移动子网解决方案。与MIP4工作组草案的方案相比,通过公用一个外地代理转交地址,减少了IPv4地址的消耗,减少了需要建立的隧道数目和切换的时延。为了验证本方案的有效性,在参考Dynamics工作组的开源代码基础上,本文在Linux系统上结合IEEE 802.11无线网卡设计了一个原型系统,在家乡代理,外地代理和移动路由器三个实体上运行软件,在用户空间处理代理发现和注册过程的消息,使用Netlink套接口与内核进行通信,修改路由策略及相关设备信息,在内核空间处理隧道转发过程,实现了移动子网功能。移动路由器为移动子网节点提供路由服务,内部节点无需具备移动功能。测试结果表明,本方案相关消息格式以及各实体的行为符合移动IPv4协议和MIP4工作组草案的定义,具有在外地代理转交地址模式下的移动子网功能。更多还原

【Abstract】 Mobile network is the hot topic in recent research with the advancement of wireless communication technologies. Popularization of mobile devices such as notebooks stimulates people’s desire of accessing Internet at any time anywhere. The entire moving network deployed on vehicles like ships and trains is one of the research emphases.IETF issues Mobile IPv4 protocol, which supports terminal mobility above the IP layer. The working group MIP4 submits a draft, which gives a scheme of network mobility on co-located care-of address mode by extending Mobile IPv4 protocol, but there is no scheme of network mobility on foreign agent care-of address mode.This paper gives a new scheme to achieve network mobility on foreign agent care-of address mode by extending Mobile IPv4 protocol and adopting the denotation and message format of MIP4 draft. Compared with MIP4 draft, it costs fewer IPv4 addresses, needs fewer tunnels and less handoff time by sharing a foreign agent care-of address.To validate this scheme, this paper designs a prototype of software in Linux system with IEEE 802.11 wireless NICs in reference to the open-source software of Dynamics group. This scheme runs software on the three entities of home agent, foreign agent and mobile router to achieve network mobility. It deals with agent discovery and registration in user space, communicates with kernel by Netlink socket, amends routing policy and corresponding device information, and deals with tunneling in kernel space. Mobile router supplies routing service for mobile network nodes, which don’t need to support mobile function.The test result shows that the message format and the behavior of the three entities in this scheme are compatible with Mobile IPv4 protocol and MIP4 draft, and support network mobility on foreign agent care-of address mode.更多还原