To estimate the link loss rates using network tomography, this paper proposes a Fast Path-based Approach (FPA) by
explicit estimation. Instead of inferring the link loss rates directly, we first infer the path loss rates from which we can
easily derive the link loss rates. In addition, the path loss rates are inferred by a new estimator which is an explicit
function of loss observations. The presented estimator is analytical and only requires simple arithmetic calculation. It is
also proved to be consistent and have the same asymptotic variance as that of the maximum likelihood estimator (MLE).
The simulation results show that the FPA can accurately estimate the link loss rates.