Patent US 9,306,822

A system and method for performing a first diagnostic test on a first class of service on a network link during a current measurement period, performing at least one further diagnostic test on a second class of service on the network link during the current measurement period, determining whether an alert was present during a previous measurement period and generating a current failure alert based on results of the first and the at least one further diagnostic tests if an alert was present during the previous measurement period.