Modern industrial environments are too complex to be managed as a single, flat network. To maintain both efficiency and security, systems must be structured in layers, each with its own purpose, technologies, and communication rules.
The Purdue Model, one of the most influential frameworks in industrial cybersecurity, provides this structured approach.

• Level 0: Physical process (sensors, actuators)
• Level 1: Control (PLCs)
• Level 2: Supervisory (SCADA, HMIs)
• Level 3: Operations (Production management)
• Level 4: Business (ERP, IT systems)

By organizing these levels, the Purdue Model helps companies understand how information and control flow between operational and managerial layers and, most importantly, where security boundaries must be established