一种支持用户快速移动的二层数据包转发策略  

A Layer-2 Forwarding Policy for the Fast Moving Users

作　　者：黄家善[1] 邹复民[1] 蒋新华[1] 

机构地区：[1]福建工程学院下一代互联网应用技术研究中心,福建福州350108

出　　处：《铁道学报》2010年第6期109-113,共5页Journal of the China Railway Society

基　　金：福建省科技计划项目(2005HZ10012007I0002)

摘　　要：针对铁路无线Mesh网络这种用户移动速度快、Mesh节点间切换频繁的应用场景,研究一种高效的数据通信方案。虽然二层转发相比三路由具有更好的移动性支持,但本文通过形式化分析发现,网桥的二层数据包转发策略可保证的路径更新延时为CAM表项的超时阈值timeout,不适用于铁路无线Mesh网络,然后提出一种主动位置告知策略实现转发路径的实时更新,并在此基础上设计一种基于端口记忆和主动位置告知的二层数据包转发策略CFP-ALN(CAM based Forwarding Policy with Active Location Notice)。研究表明,策略CFP-ALN不仅可保证快速移动用户最低的切换延迟,并且只需要增加一个单播数据包的网络开销,具有良好的实用性。This paper is to study an efficient data communication scheme for the railway wireless Mesh network,which supports rapid,mobile and frequent handoff.Although the layer-2 forwarding policy has more mobility support than the layer-3 routing,it is approved that the CAM based Forwarding Policy（CFP） is unsuitable for the railway wireless Mesh network,and then an Active Location Noticing Policy（ALNP） is proposed to update the forwarding path in real-time when the fast moving user switches from one AP to another.On the basis of these two policies,the CAM based Forwarding Policy with Active Location Notice（CFP-ALN） is presented.Theoretical analysis results show that CFP-ALN is practical with the lowest handoff latency and low bandwidth cost.

关 键 词：铁路无线Mesh网络 二层转发策略 快速移动用户 主动位置告知 

分 类 号：TN929.5[电子电信—通信与信息系统] U284[电子电信—信息与通信工程]