Technology Research, Based On The Topology Of The Network Tomography Reconstruction

The heterogeneous and no-corporative structure of the Internet makes the traditional network measurements which requires the cooperation of internal node facing great challenge, while the way based on network tomography has already been much more important in network measurements, which infers the network internal performance or logic topology only by end-to-end measurements.We have made great achievement in network performance inference based on tomography technology. But as far as topology inference is concerned, we only make contributions to the multicast topology inference by end-to-end loss, while we have done much less on the research on the topology inference by end-to-end delay and works under unicast condition. In order to solve these problems, we do works as below in this paper:1. Do research on the estimation of shared loss ratio, multicast topology inference by end-to-end loss, the estimation of non-parametric discrete distribution of cumulative delay and delay distribution-based topology inference using delay average and variance as metrics. In so far as the disadvantages brought by fixedξin GLT algorithm, this paper proposes an improved algorithm IGLT based on the grouping method with less computation, which dynamically adaptsξaccording to the estimation of link loss-ratio. And the MATLAB simulation results show the efficiency of the algorithms.2. It is suggested to use packet-pair as the probes for loss-related and the delay-related topology inference under uincast environment because of the limitation of multicast protocols and the popularity of unicast probes on networks. In order to strengthen the correlation between probes and indeed improve inference accuracy, we do research on a probe-sending method called three-packet stripes and apply it to both the loss-related and the delay-related inference in unicast tomography for the first time. At last, we use OPNET to build simulation environment and the results show greater performance of three-packet stripes compared with packet-pair sending method.