Modern automation and control systems are heterogeneous in communication. Besides fulfilling the main automation function in an optimal way, reliability of the system comes into focus. Especially the communication infrastructure is important for reliability. Network breakdowns can be detected easily. More difficult is to evaluate is the dynamic change of the behavior of the network traffic and network timing to detect degradation. The tasks related to network asset management comprise detection of failures and potential problems, as well as generation of indicators for network fitness. All this has to be done for hierarchical, multi-layer networks across the automation pyramid. Hence, the definition of abstract indicators capable of mapping to different networks is necessary. This paper analyses potential sources for such indicators and provides a concept for application in industrial networks.