Definition
The Purdue Model (ISA-95) is a reference architecture for industrial control systems that divides the network into hierarchical levels, from the field level (sensors, actuators) via SCADASupervisory Control and Data Acquisition - system for real-time monitoring and control of industrial processes. and DCS up to enterprise IT. The model defines which systems may communicate with each other and forms the basis for security zone thinking in OT environments. In the light of IT/OT convergence and NIS2EU directive on network and information security - imposes strict security requirements on critical infrastructure., the Purdue Model is under pressure, but remains an important reference point.