Vijay Nair

Department of Statistics

University of Michigan


Active Network Tomography and Bicast Probing Experiments

Estimation of quality of service parameters, such as packet loss rates and delay distributions, is of considerable importance to network administrators and service providers. We consider the active network tomography problem where the goal is to estimate packet loss rates and delay distributions of all internal links in a network from measurements obtained from nodes located on the periphery. This is an example of a large-scale statistical inverse problem. We will provide a brief review of the literature, including unicast and multicast probing schemes and introduce a new method called bicast probing. Several methods of estimation for loss rates and delay distributions will be described, including the use of EM-algorithms for the MLEs and several classes of least-squares estimates for loss rates. Some practical issues and results from simulation studies will also be discussed.


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