摘要： IETF提出的移动IP协议对微移动的支持不够，而分布式路由方案能较好地解决该问题。该文在一种分布式移动IP方案的基础上进行了改进：将转向代理的缓存修改为循环列表，减少移动节点接收的乱序分组；当切换转向代理时，移动节点向前一个转向代理发送绑定更新消息，减少转向代理切换时的分组丢失；在转向代理处引入Snoop机制，减少通信对端重传分组数。利用NS2软件对两种方案进行了仿真。仿真结果表明，改进的方案能够明显地减少重传分组和乱序分组，进一步减少远程信令流量和数据流量，提高网络资源的利用率，有效地改善移动IP的性能。

关键词: 移动IP, 分布式路由, 转向代理, 局部代理

Abstract: Mobile IP solves the macro-mobile problem in the network layer, but it’s not a good solution for micro-mobile problem. As distributed routing can settle the problem, optimizations are proposed to a distributed-agent scheme in order to improve the performance further, i.e. change the buffer in redirection agent to circular list, in order to reduce the number of the out-of-order packets; when shifts redirection agent, the mobile node sends binding update message to the former redirection agent, in order to decrease the number of the lost packets; introduce Snoop mechanism to the redirection agent to reduce the number of the retransmission packets sent by the correspondent node. Results from simulation confirm that both the retransmission packets and the out-of-order packets are reduced, remote signaling and data traffic are decreased, and the utilization of the network resource is enhanced. The performance of mobile IP is improved effectively using this scheme.

Key words: mobile IP, distributed routing, redirection agent, local agent

中图分类号: 

• TP393