Research On IP Network Measurement And Traffic Performance

With the explosive development of the scale, the number of users, and services types of IP networks, more rigorous schemes to operation, administration and maintenance are required for building network infrastructure with high QOS and perfect information security. And it is important to master the behavior of IP network for research and development of network device and protocols. Thus, the research on network measurement and traffic performance is paid more attention.This paper focused on IP network measurements and traffic performance analysis, which aims at building an effective network measurement infrastructure, and mastering the end-to-end and traffic performance characteristics of IP networks. The final objects are to give better comprehension of network behaviors, to improve the QoS, to solid the security ability and to build a basis for development of new protocols. The main work and results of this paper are as follows:1. The conventional methods to measure one-way delay rely on GPS receiver or NTP protocol to keep synchronization between sender's clock and receiver's clock. However, GPS receiver is not ubiquitous in price and environment and NTP protocol is low in accuracy. A new method based on nonlinear programming, which can remove the skew and offset between the two clocks, is presented. Measurement results show that the method works well. Nonstationarity and nonlinearity are found by analysis of various delay series measured from different links. And different types of links, different Self-Similarity. By constructing appropriate network architecture and neural functions, functional networks can be used to identify Internet end-to-end nonlinear delay time series. Furthermore, by using adaptive parameter studying algorithm, the nonstationarity can also be well modeled. The results show that the functional network architecture can precisely characterize the Internet end-to-end delay dynamics.2. Several measurement methods of network bottleneck bandwidth, with their advantages and disadvantages are discussed. An enhanced method is presented in which new decision rules are added into multi-packet method by analyzing the stationarity and the ratio of standard deviation to mean of probing packets interarrival time series. The simulation results show that the method eliminates the error caused by time compressing or expanding which packet pair method can't overcome, improves the precision than multi-packet method and works well under heavy loads. A new active measurement approach to Internet end-to-end available bandwidth estimation is proposed, which is based on the concept of self-induced congestion. In this approach,the transmission rates of probing packets are increased step by step and a new decision criteria, NWID (Normalized Weighted Increased Delay), is defined. Another idea is that sliding-window decision is adopted. Simulation results show that the measurement precision is improved with slightly adding probing overhead compared with pathchirp.3. Simulation results show that the aggregate traffic at Access Point (AP) of IEEE 802.11 WLAN can be better classified as a multifractal or multiscale stochastic process. Based on the new results on multiscale queuing analysis, the performance of the traffic loss rate with variable buffer size is analyzed. The simulation results are consistent with the numerical results. Furthermore, a new QoS-oriented Hybrid Admission Control (QHAC) scheme in IEEE 802.11 WLAN is proposed, in which the influence of the mobile station with slow speed on others is decreased by limiting its inter-request time. In addition, end-to-end performance metrics are also measured and applied to make a decision for admission control of new request. Simulation results show that QHAC scheme can efficiently improve the performance of IEEE 802.11 WLAN.4. A D-BMAP/D/1 queuing model is applied to analyzing the performance of GPRS data services, such as mean RLC/MAC queue length, mean delay and loss rate of mini-packets, in which a simplified one-phase access procedure, different ser...