Time-varying network link loss rate is a useful information for network managers to discover and locate the network link failures. This paper proposes a method to track time-varying network link loss rates from unicast end-to-end measurements. The method first trains a state transition matrix to capture the spatio-temporal characters of packet link transmission probabilities by sending end-to-end probe packets and then estimates the time-varying link loss rates using the state transition matrix and the end-to-end measurements obtained from background traffic (the existed packets in network). We also introduce a validation step to check and retrain the state transition matrix in order to ensure the accuracy of the state transition matrix. Our method is capable of tracking the variation of link loss rates without incessantly sending probe packets, which is very feasible for many practical applications. The ns-2 simulation results show the good performance of our method.KEYWORDS end-to-end measurement, link loss rate, network tomography, time-varying
INTRODUCTIONWith the rapid development of the network technology, the scale and the complexity of the Internet are increasing sharply. In order to efficiently design, control, and optimize the network, it is essential to timely understand the accurate network internal performance parameters, such as link loss rate and link delay. Traditional methods obtain the network internal performance parameters by measuring them directly on the basis of the cooperation of internal nodes. However, these methods fail if the cooperation of the internal nodes is infeasible because it may incur security problem to the network.Network tomography 1,2 is regarded as a promising technique in network measurement field, because it can infer the network internal performance parameters (such as link delay, 3,4 link loss, 5-10 link bandwidth, 11 and neutral link, 12 etc) without deploying monitors inside the network. This technology can also be extended to infer network topology 13,14 and traffic matrix. 15,16 Since it is more practical and scalable than the internal cooperation-based methods, network tomography has attracted many studies since it was proposed.Network link loss inference (also called loss tomography) is an important component of network tomography, and numerous ways have also been developed to infer link loss from end-to-end measurements. However, most of these methods are under the assumption that the link-states are stationary, and the loss rates remain unchanged in the measurement period. The link loss rates are estimated by sending amount of probe packets from a source node to a set of destination nodes.In actual, the bursty property of network traffic makes the link-states change frequently, and the link loss rates can also be varied with the changing of the link-states. Hence, it is necessary to send the probe packets incessantly in order to Int J Commun Syst. 2019;32:e4070.wileyonlinelibrary.com/journal/dac