Pattern DD-C

OT export out, control or updates in

Two links in opposite directions, each with its own approval and its own decision owner.

Request a quote Talk to an engineer

Area: Data diodes
Environments: 3
Products used: 4

How it is built

One-way path
Data path

Two links in opposite directions, each with its own approval. Not one bidirectional path.

Used in these environments

SCADA export to the office networkThe direction that matters is out. Everything that wants to come back in is a separate decision with its own owner.
Patch distribution into a closed networkThe direction runs towards the protected side, which inverts every assumption the other flows rest on.
Medical technologyGalvanic isolation is a double argument here: security, and fiber neither picking up nor radiating interference near diagnostic equipment.

How it works

Two links in opposite directions, each with its own approval and its own decision owner. That is the whole design. Measurements and events leave the OT network continuously; updates and control enter it rarely, deliberately, and through a different device.

Why they are not one bidirectional link

Two diodes in opposite directions stay two diodes as long as they are physically separate and neither one’s traffic depends on the other’s. The moment an application on one side waits for something that arrives on the other, the pair has become a bidirectional link with extra steps — and the assessment that approved it no longer applies.

The direction that gets underestimated

Inbound is the hard one. Everything that enters a protected network is an opportunity, and the diode does not inspect content. Content disarming, a staging zone, and an explicit decision about who may release an update belong to the inbound path, not to the diode.