@INPROCEEDINGS{C10-ITC22,
   AUTHOR       = {Roberto G. Cascella and Chadi Barakat},
   BOOKTITLE    = {Accepted to the 22nd International Teletraffic Congress (ITC 22)},
   TITLE        = {Estimating the access link quality by active measurements},
   YEAR         = {2010},
   ADDRESS      = {Amsterdam, The Netherlands},
   MONTH        = {September 7-9, 2010},
   KEYWORDS	= {end-to-end measurements, quality of Internet access, access link characterization},
   ABSTRACT	= {The access link quality experienced by the end users depends on the amount
		   of traffic and on the presence of network anomalies. Different techniques
		   exist to detect anomalies, but little attention has been devoted to
		   quantify the access link quality and to which extent network anomalies
		   affect the end user's access link experience. We refer to this aspect as
		   the \textit{impact factor} of the anomaly, that we define as the percentage
		   of affected destinations. In the ideal case, a node should continuously
		   monitor all possible routes to detect any degradation in performance, but
		   this is not practical in reality.

		   In this paper we show how a node can estimate the quality of Internet
		   access through a limited set of measurements. We initially study the user's
		   access network to understand the typical features of its connectivity tree.
		   Then, we define an unbiased estimator for the quality of access and we
		   compute the minimum number of paths to monitor, so that the estimator
		   achieves a desirable accuracy without knowing the underlying topology. We
		   use real data to construct a network graph and we validate our solution by
		   causing a large number of anomalies and by comparing the real and the
		   estimated quality of access for all available end hosts. Our results show
		   that the impact factor is a meaningful metric to evaluate the quality of
		   Internet access.},
}