Implements OT network segmentation using VLANs, OT-aware firewalls, data diodes, and IEC 62443 zone/conduit architecture, with a traffic-baseline-driven design tool for migrating flat Purdue-model networks without disrupting operations. Use when segmenting a flat OT network into Purdue levels, deploying an IT/OT DMZ, or isolating safety instrumented systems from basic process control systems.