Passive network tomography using em algorithms

The paper presents a new method for characterizing communication network performance based solely on passive traffic monitoring at the network edge. More specifically, we devise a novel expectation-maximization (EM) algorithm to infer internal packet loss rates (at routers inside the network) using only observed endto-end (source to receiver) loss rates. The major contributions of this paper are three-fold: we formulate a passive monitoring procedure for network loss inference based on end-to-end packet pair observations, we develop a statistical modeling and computation framework for inferring internal network loss characteristics, and we evaluate the performance with realistic network simulations. 1