A baseline for internet traffic duration is established by (i) collecting internet traffic data regarding file size, server response time, packet loss and round trip time, (ii) removing from this data outliers associated with file size, server response time and packet loss per client type, and (iii) organizing any remaining data into round trip time bins according to median values of round trip time per client type. Thereafter, historical or newly collected Internet traffic data is compared against threshold values for each round trip time bin to locate duration outliers. These duration outliers are indicators of congestion and congestion episodes may be identified by the continued presence of such outliers over successive time intervals.