Research And Implementation Of One Way Network Oriented Time Delay Measurement

Network one-way delay is one of the most important parameters in various network performance indicators which are widely used.The accurate measurement of the one-way delay of the packets can reflect current network congestion situation.Traditional method has a large error in the asymmetric network environment.In light of this situation,the paper implements two one-way delay measurement algorithms.A one-way delay measurement system is also implemented.The detailed research content can be divided into three parts:1.If the inherent propagation time of the detection packet is basically equal in the round-trip link,the delay asymmetry of the round-trip link is mainly caused by the queue delay.This paper proposes a network one-way delay measurement method based on the elimination of queue delay(Eliminate queuing delay algorithm,EQD).This algorithm effectively improves the accuracy of the clock offset by eliminating the queue delay,and further improves the calculation precision of the one-way delay.In order to accurately calculate queue delay,this paper proposes a method based on frequency fitting to calculate queue delay algorithm(RTCQD),the RTCQD algorithm increases the average accuracy by more than 50%.2.If the probe packet passes through different routers between uplink and downlink,the inherent propagation time is quite different,network asymmetry is mainly caused by propagation delay.There is a great error in the one-way delay based on two-way message communication.In view of this situation,this paper proposes a Circle Path delay algorithm(CPD),the third auxiliary node is introduced to build a triangle message communication model.By measuring the RTT of packet,a set of equations composed of one-way delay are established.To improve the accuracy of computation,this paper reduces the estimation range of one-way delay by using the propagation delay and queue delay of the detection packet,and finally calculates the one-way delay with the least square error(LSE).3.The network one-way delay measurement system is realized and providing real-time measurement and historical query function.Results are displayed on the web side in a graphical form.The two methods are verified in two different actual link environments,respectively,and experimental results are compared with the GPS.The algorithm can effectively eliminate the influence of network asymmetry and network congestion.Compared with the traditional one-way delay measurement algorithm,the accuracy of EQD algorithm and CPD algorithm are both increased by 30%.In this paper,two algorithms are designed and implemented to accurately measure the one-way delay in an asymmetric network environment.The experimental results show that these two algorithms can accurately calculate the one-way delay in the network asymmetric environment,which have important theoretical significance and research value.