【摘要】 为了使支持服务质量(QoS)路由的路由器获得网络中实时变化的QoS状态,提出一种部署在QoS路由器上的分布式实时测量方案,直接在现有链路上测量有向链路可用带宽、时钟差、分组传输延迟和分组丢失率等参数。测量手段为主动测量和被动测量相结合,采样方法为分层随机采样,数据处理为指数移动平均和中值,测量得到的结果通过QoS路由协议传播给其它QoS路由器。该方案已经在服务质量路由器原型系统上实现。分析和实验结果表明:该方案无需第三方设备就可满足所需的精度,测量结果既反映最新的网络状态又具有相对的稳定性。测量分组在每条链路上仅占用2kb/s的带宽,且和网络规模无关。更多还原

【Abstract】 The fluctuating network QoS states for routers supporting quality of service(QoS) routing were measured using a distributed real-time measurement scheme.The scheme directly utilizes existing links to measure one-way available bandwidth,clock offset,delay,and loss rate.Samples are collected by passive sampling and active sampling,which uses stratified random sampling.An exponential moving average and median are used for data processing.The measurement results are propagated to other QoS routers by QoS routing protocols.Analysis and test results show that the scheme provides the desired accuracy without any extra devices.The results reflect the latest network states and gain relative stability.Measurement packets occupy only 2 kb/s of bandwidth on each link,which is not significant relative to the scale of network.更多还原