Research On Available Bandwidth Measurement Technology Of High Precision Network

Our life is inseparable from the Internet,and the network system is becoming larger and more complex with the rapid development of the Internet.Network monitoring and diagnosis technology plays a vital role in daily network management and network performance optimization.However,the existing network monitoring and diagnosis technologies are usually accompanied by problems such as high measurement overhead and weak tool practicability,which the end-to-end network available bandwidth measurement technology is a typical example.Currently,the commonly used methods for measuring the available bandwidth of an end-to-end network are divided into active network measurement and passive measurement.The active network measurement methods consume less measurement time in the measurement process,but it will inject additional probe traffic into the network,which has a significant impact on the network.The passive network measurement methods are to deploy a traffic collection device in the measurement link,and obtain more accurate results by continuously collecting and analyzing the traffic,but the measurement time is long and a large amount of measurement resources are consumed.The solutions proposed in the literature related to the existing active network measurement methods mainly include two categories: PGM(Probe Gap Model)and PRM(Probe Rate Model).This thesis sorts out and summarizes the active network measurement methods based on the above two models,and proposes a measurement packet sequence form to measure the available bandwidth of the end-to-end network based on the problems existing in the existing active network measurement and detection model methods.The probe sequence consists of load measurement data packets with approximately exponential distribution in the middle part and position probe data packets with TTL decreasing on both sides.The high-precision network bandwidth measurement system that can diagnose the location of tight links,where tight links refer to the path with the smallest available bandwidth.The system proposed in this thesis is in the form of embedded hardware and controlled microsystems,including: measurement probes and measurement consoles.The system can effectively reduce the measurement overhead and measurement time,and improve the problems that the existing active network measurement methods have a large impact on the network,and realize the high-precision and high-efficiency measurement of the available bandwidth of the end-to-end network.The following points of research are included in this thesis:Firstly,we reviewed the existing network measurement schemes and available bandwidth measurement schemes,pointed out the feasibility and limitations of existing end-to-end network available bandwidth measurement schemes.Secondly,the basic design architecture and implementation scheme of the system are proposed by analyzing the existing active measurement algorithms.Thirdly,the module design of the embedded hardware part involved in the measurement system proposed in this thesis is implemented on FPGA.The function,principle and signal meaning and type of each module are briefly introduced,and the function simulation of each module is realized by Modelsim software.Fourthly,the test platform network is built by GNS3 software.After cascading the entire system,measure the available bandwidth of the built test network,and compare the results with the existing measurement scheme.From the verification results,the completeness and accuracy of the function of the measurement system designed in this thesis can be obtained.