An autonomous distributed expert system for switched network maintenance

The authors describe TOPAS (trunk operations, provisioning, and administration system)-ES, an expert system that diagnoses transmission and signaling problems arising on telephone trunks in the AT&T long-distance network. It runs autonomously, issuing operations system commands to retrieve trouble reports and perform measurements on the problematic trunks. It is also a distributed system, since different copies of TOPAS-ES must communicate with one another in order to coordinate the diagnosis process from both ends of a trunk. The three software subsystems of TOPAS-ES are described in detail, namely, the inference subsystem, the communications subsystem, and the graphical end-user interface