Techniques are provided for improved fault isolation and fault reduction. A system for use with a data network includes multiple diagnostic units each adapted to communicate with the network including to a network user. A central controller is operatively connected to the diagnostic units, the controller being adapted to communicate with and coordinate operations of the diagnostic units, to instruct the diagnostic units to perform tests adapted to help isolate a network fault, and to analyze test results received from a diagnostic unit to attempt to determine the network fault. Various methods for improving fault isolation and fault reduction are also provided.