Patent Number: 
Section: claims

1. A diagnostic device for use in a communication network comprising network equipments, said device comprising:diagnostic means that are adapted to determine the cause of problems occurring within said network on the basis of information provided by said network equipments, the diaanostic means comprising;a knowledge base in the form of basic diagnostic units, andprocessing means comprising a rules engine adapted to establish hierarchical associations between basic diagnostic units selected in said knowledge base by means of selected rules to constitute configurable diagnostic models adapted to determine said causes of said problems. 2. The device claimed in claim 1 wherein at least some of said rules are of a statistical or probabilistic type. 3. The device claimed in claim 2 wherein said processing means are adapted to associate selected statistical or probabilistic weights with at least certain of said basic diagnostic units and/or at least certain of said rules and/or at least certain of said models. 4. The device claimed in claim 1 wherein said processing means are adapted to associate at least some of said basic diagnostic units by means of selected models. 5. The device claimed in claim 1 wherein said processing means are adapted to associate certain selected basic diagnostic units in selected trees constituting certain of said diagnostic models. 6. The device claimed in claim 1 wherein said processing means are adapted to associate selected administrative costs with at least certain of said basic diagnostic units and/or at least certain of said rules and/or at least certain of said models. 7. The device claimed in claim 1 wherein at least certain of said diagnostic models take the form of a Bayesian network. 8. The device claimed in claim 1 wherein at least certain of said basic diagnostic units take the form of a Bayesian network. 9. The device claimed in claim 1 wherein at least certain of said basic diagnostic units take the form of sets of hierarchical tests. 10. The device claimed in claim 1 wherein said processing means are adapted to modify at least certain of said basic diagnostic units and/or at least certain of said rules and/or at least certain of said models and/or .at least certain of said statistical or probabilistic weights and/or at least certain of said administrative costs. 11. The device claimed in claim 1 wherein said processing means comprise a man/machine interface adapted to enable a user to effect said associations and/or said modifications.