Research And Implementation Of Bandwidth Measurement Technology For Air-Ground Broadband Link Network

The high latency of satellite communication links in the air-ground broadband context can easily cause messages to block at the bottleneck bandwidth and cause network congestion,while satellite communication links are susceptible to effects such as space interference,signal fading,and shadowing effects,which make the link BER orders of magnitude higher than that of wired transmissions.The high BER reduces the ability of satellite links to reliably transmit data.Therefore,quality of service(Qo S)is required before satellite communication link transmission to ensure effective delivery.Qo S does not create additional bandwidth;it allocates bandwidth based on current network capacity,so Qo S requires network measurements to provide bandwidth metrics.In this thesis,bandwidth measurement software development work is carried out in the context of air-ground broadband links to study the effectiveness of enhancing bandwidth measurement software in this context.Based on the above background,this thesis analyzes the current development status of network bandwidth measurement algorithms at home and abroad,and combines the pre-research requirements of the demand side to sort out the functional modules of the bandwidth measurement software,and the overall design of the bottleneck bandwidth measurement software and the available bandwidth measurement software.During the design of the bottleneck bandwidth measurement software,based on the context of the software usage,the message pair measurement method is adopted here and optimized by generating a unique identification number for the sender's messages.Client-side and server-side are divided by function,and client-side software functions include probe packet construction,timestamp writing,message identification number generation,message pair interval setting,and probe packet sending,etc.Server-side software functions include probe packet capture,message pair intra-interval calculation,and post data processing process.In the data processing process,the measurement results obtained by the statistical analysis method under heavy load show multifractal characteristics,and the measurement error is large when used directly.In this thesis,we optimize the measurement process: after getting the asymptotic discrete rate value,we obtain the measurement results of different size of message pairs passing through the link,compare the measurement results with the discrete rate value,take out the results larger than the value and do the mean processing,which is the estimated value of the bottleneck link.Finally,the pre-study requirements are completed by comparing with other measurement methods.During the design of the available bandwidth measurement software,some functional modules are similar to the bottleneck bandwidth,mainly the differences in the message size and interval setting at the sender side and the data processing at the receiver side.Combined with the usage background,this thesis improves the determination conditions of the algorithm at the turning point based on the principle of IGI/PTR algorithm.In the air-ground broadband link scenario,the original algorithm determination condition does not consider the loss of detection messages.In this paper,the sum of the intra-pair interval of all messages is calculated by the average value of the intra-pair interval of the messages at the receiving end,and the sum of the intra-pair interval of the messages at the sending end is used as the input of the decision condition at the turning point.Finally,the project pre-research requirements are completed by software testing.