The Research On Bandrate Measuring Based On Packet Pair

Research on network measurement methodologies is an important filed for network related researches in last decade, and has been a hot spot in recent years. The aim of network measurement is to evaluate the operation of network, develop measurement-based analytical model for network metrics, lift the performance of underlying communication networks and optimize the network system design and flow engineering.Network bandwidth is one of the most important performance metrics. Many network applications' performance depends on path's bottleneck bandwidth or available bandwidth. Accurate network bandwidth measurement could provide necessary information for many network applications, such as dynamic multicast routing tree, selection of server, rate adaptation in streaming media application, verification of SLAs and so on.Packet pair algorithm is one of the basic technologies for network measurement, and now it has been widely applied to measure end-to-end path bandrate. the present models and approaches of bandwidth measurement are analyzed , And the comparisons of performance and applicability between them are also given. Based on theoretics analysis and experimental results , the disturbance factors influencing the accuracy of packet pair algorithm is studied in depth., e.g. Cross traffic, packet pathology, clock precision. then behavior Characteristic of packet pair are deeply analyzed and quantified.To deal with theses disturbance factors, an optimization strategy is proposed and implemented. In this strategy a four-packets-based method and bandwidth-adaptive packet pair algorithm is proposed and implemented.①In this thesis, The effects of bandwidth estimator's clock resolution to the accuracy and stability of the packet pair algorithm are deeply analyzed and quantified. A bandwidth-adaptive packet pair algorithm is proposed and implemented.②The cross traffic can disturb the packet pair, so the key of packet pair technique is choosing good filtering algorithm. This article analyzed the relation of the measurement result by two packet pairs with different size, then presented a four-packets-based method for measuring end-to-end path bandrate, the four packet is consisted of two packet pairs with different size.On this foundation, a tool for network bandrate measurement, is designed and implemented. Experimental result show it can improve the accuracy and stability abundantly.In the end, by measuring and analyzing network performance of the Hunan University Campus LAN, we preliminary summarized the performance characteristic and draw a lot of valuable conclusions.