Automated network diagnostic techniques

A system comprising:

• one or more processors;
• and
• one or more nontransitory computer readable media including instructions which, when executed by one or more processors, cause the one or more processors to:
• collect, during a plurality of time periods spanning a plurality of days, a plurality of Layer-4 protocol statistics for Layer-4 network connections each having a first endpoint at one of one or more client devices, wherein data transmitted for each of the Layer-4 network connections traverses the communication network, each of the time periods being at least 5 minutes in duration and the plurality of days including two nonconsecutive days;
• determining, for each time period in the plurality of time periods, a first Layer-4 condition metric for the time period based on the Layer-4 protocol statistics collected during the time period;
• determine a first network performance indicator, based on a number of the plurality of time periods that a first threshold condition is met by the first Layer-4 condition metric;
• determine whether the communication network has experienced a performance issue based on the first network performance indicator meeting a second threshold condition;
• and
• cause a diagnostic action, a corrective action, or a maintenance action to be performed based on the determination whether the communication network has experienced a performance issue.