Ad hoc无线网中DSR协议缓存优化的研究

Research on cache optimizing in DSR route protocol for wireless ad hoc network

DSR协议是一种性能优越的按需路由协议,但是因为节点的移动和连接的破坏使得其缓存中的路由信息容易失效,目前主要的解决方法是:对一个连接或者一条路由设置生存期,通过时间限制机制来解决路由失效问题,但是这种方法还存在问题:生存期不能精确反应网络的拓扑变化.因此引进一种新的方法:通过自适应缓存更新算法来主动传播破坏连接信息到所有保存了该破坏连接的节点中,主动更新缓存.仿真结果表明:自适应缓存更新算法能够快速适应网络拓扑结构的变化,在数据包传输率,传输时延及路由开销方面均优于基于路径缓存和连接缓存的DSR协议.

DSR is a good protocol in on-demand route protocol. Due to mobility and line broken, the route information stored in the cache will be easily invalidated. In order to solve the problem, the lifetime of a link or a route is configured and the invalidated route problem could be solved through the time mechanism, But there is still a problem in this way. It can＇t reflect the topology change of the network. In this paper, we introduce a new method： updating the cache＇s route by a distributed adaptive cache update algorithm, to disseminate the broken link information to the nodes that have cached the broken link. The result of simulation shows： the new algorithm make route caches much more adapt to the topology change. It is more advantage than the DSR protocol based on the path cache and link cache in pocket delivery ratio, pocket delivery delay and route cost.