Abstract: A network, in particular a telecommunication network, with surveillance sensors and a diagnostic system comprises equipment for conveying signals to network users, sensors for supplying data on network operation and a diagnostic system processing this data to establish diagnostics designating causes of degraded operation. The diagnostic system performs diagnostic evaluation to request secondary data if a previously established diagnostic is insufficient.

Abstract: An expert system capable of meeting real time constraints for solving a problem on the basis of a flow of input messages concerning the operation and the status of a network of machines, this status changing with time, includes a filter module detecting in real time significant events on the basis of input messages, each significant event being a manifestation of a problem, as judged by a human expert. A database stores all input messages, the significant events defined by the filter module, intermediate data produced by the expert system, data constituting a model of the network of machines and archives relating to problems processed previously, whether solved or not.