Abstract: Apparatus for module level management of a network having a plurality of network devices, comprises, supervisory layers at the module units on a plurality of network devices for supervising expected communication behavior thereat. Expected communication behavior includes protocol and interface definitions and the like. The supervisory layers detect deviations from expected communication behavior at the self contained modules. As a result, devices behave in an expected way and are less likely to cause the kinds of problems which easily escalate on networks. Furthermore, causes are dealt with before they can develop into symptoms.