Study On Analyzing And Measurement Of IP Network Delay Characteristic

The Internet, which is based on TCP/IP protocols, has been developed rapidly in the last decades, and also has been used widely. It reforms the working, learning and living manners of human society. However, network QoS, manageability, and network models, etc, promote challenges for further development of the Internet. Due to the inherited heterogeneity, complexity, openness and dynamic natures of the Internet and the fast evolution of networks and applications, throughout understandings of network behaviors are needed imperiously, for monitoring, managing and modeling the network as a whole, and for guaranteeing network quality of service, especially the end-to-end QoS.Researches on end-to-end Internet performance monitoring or measuring techniques will provide scientific references and powerful assistants to the areas such as: Internet management and controlling, network planning and utilization, the developing and deployment of high efficient protocols, devices and applications. In this thesis, we surveyed the state of the art in end-to-end Internet performance measurements, reviewed the past progresses in this area, analyzed the definitions of performance measurement metrics framework, the classifications and evaluation criterions of measurement methods, and summarized the states and characteristics of existed large scale end-to-end Internet performance monitoring systems. Based on this, this thesis analysis the technique for round trip time measurement, and analysis the characteristics of network round trip time. The main innovative achievements of this thesis are as following:A careful comparison was done of different software and hardware configurations for measuring the round trip time, as well as the repeatability of measurements on similar configurations. The results show that ping's own RTT measurements can contain significant source processing delay and so distort the analysis of traffic patterns; running tcpdump to capture the packet wire times increases the accuracy of RTT measurement; running tcpdump on separate measurement machines in single-user mode with output to the RAM disks can generate consistent WRTT measurements.Findings in the pattern analysis include: short term high density ping traffic patterns can sometimes be interpreted by buffering and queueing models; the size of measurement packets can significantly influence traffic behavior; due to source host factors ping request packets may be sent out of sequence.