Zone and conduit model

The zone and conduit model, developed by the ISA99 committee that authors ISA/IEC 62443, groups an OT network into "zones," sets of assets that share the same cybersecurity requirements, and "conduits," the communication pathways connecting those zones that also share a consistent security policy. Rather than trying to secure every device individually, this model lets an organization apply a consistent, appropriate level of protection to each group and control what crosses the boundary between groups.