This article introduces a simple and effective methodology to determine the
level of congestion in a network with an ECN-like marking scheme. The purpose
of the ECN bit is to notify TCP sources of an imminent congestion in order to
react before losses occur. However, ECN is a binary indicator which does not
reflect the congestion level (i.e. the percentage of queued packets) of the
bottleneck, thus preventing any adapted reaction. In this study, we use a
counter in place of the traditional ECN marking scheme to assess the number of
times a packet has crossed a congested router. Thanks to this simple counter,
we drive a statistical analysis to accurately estimate the congestion level of
each router on a network path. We detail in this paper an analytical method
validated by some preliminary simulations which demonstrate the feasibility and
the accuracy of the concept proposed. We conclude this paper with possible
applications and expected future work
