Research Of IP Network Link Utilization Measurement

Performance measurement on IP network plays an important role in research and development of network, because it can be used to analyze essential performance on Internet, such as infrastructure of network and traffic, etc. Internet is a network whose architecture, protocol and application are complicated, so its topologies are difficult to be mastered and its models are difficult to be built. Thus, measurement becomes the only method available to research Internet end-to-end dynamics, and it also becomes important to develop Internet.A novel approach to link utilization measurement, which is based on the time stamp of each hop, is proposed. The source sends probe packets, in which the current router time is recorded. The multiple probing results are processed , and the queuing delay of each probing packet are obtained, which is finally transformed into link utilization.Meanwhile, we studied the application of the link utilization measurement method in the wireless environment. IEEE802.11b is chose as a wireless measurement environment. According to the features of the wireless link, three improvement of the measurement method is developed. First, according to the wireless bandwidth, the frequency of the probe packet train is chose; Second, the measurement accuracy is improved by increasing Link-busy-state sequence values; Third, loss packet compensation algorithm is proposed for improving the impact of the high packet drop rate in the wireless link.Finally, QoS is introduced to the cable link utilization measurement. Under DiffServ environment, the link utilization about various priorities services is measured. And the accuracy of the measurement is judged, the reason for the existence of the measurement error is analysed.