OT Network

Operational Technology refers to systems that control and monitor physical processes: programmable logic controllers (PLCs), drives, sensors, and control systems in production or energy supply. The OT network is the network these systems use to talk to each other, as distinct from the IT network, which handles information for the office and administration. The split exists because the two worlds prioritize different things: IT usually puts confidentiality first, OT puts the uninterrupted availability of the plant first.

In practice, machine controllers and sensors often communicate over dedicated protocols such as Modbus or Profinet, built for a closed shop-floor network rather than open connections to the office network or the internet. The separation is usually implemented as a dedicated VLAN or a physically separate network, with a firewall in between that only allows the connections actually needed — say, a dashboard in the office pulling production data.

A common grey area: OT systems often run for decades because replacing the equipment is expensive, and in that time rarely or never receive security updates, since even a planned restart means a production stop. Separating OT from the IT network is therefore not an extra precaution but often the only practical protection available when patches simply aren't coming.