一种移动IP的外部代理分层模型--Step-HMIP

现有的移动IP规范存在两个重要的性能问题：(1)通信对端和外地链路上的移动节点之间的三角路由问题;(2)移动节点在紧密耦合的小蜂窝基站间频繁切换时会增加网络负载并加重数据包的丢失．该文针对这两个问题进行研究,给出了一个基于基本移动IP规范的外部代理分层模型——Step-HMIP模型．在此模型中引入了一个新的实体——网关移动代理,用以实现优化路由和平滑切换的功能：在NS上建立了Step-HMIP的仿真模型,对模型的主要参数测试结果表明．Step—HMIP模型在对属地代理(HA)、固定的通信对端(如Web服务器和FTP服务器)和对网络层以上协议无需进行改动的情况下．以小的配置代价就可显著优化路由,降低属地代理的注册负载和稳定了切换时的数据传输率．

Step-HMIP:A Hierarchical Foreign Agents Model for Mobile IP

Two significant performance problems exist in the current Mobile IP. First, the tunneling scheme of the Mobile IP introduces a triangle routing problem. Packets between corresponding node (CN) and mobile node (MN) are routed through a non-optimal triangle route. Second, the frequent handoffs between cellular base stations would aggravate network traffic overhead and cause in-flight packets loss during handoff. This paper proposes a hierarchical foreign agents model for Mobile IP. This model introduces a new entity, the Gateway Mobility Agent (GMA),to provide route optimization and smooth handoffs. Simulation results show that without modifying home agent, stationary corresponding node, such as the Web server and FTP server, and upper layer protocols, this model can achieve substantial performance improvement in term of route length,registration overhead, and data transmission rate during handoffs at a low cost.