Layer 1 - The process layer
The process layer of data-flow diagrams is the second layer. You should use it for most systems. Data-flow diagrams at this layer contain separate data-flow diagrams detailing each system part.
Goal: Represent secondary system parts with enough context to help you understand how they work and interact with each other.
Similar to the system layer, data-flow diagrams in the process layer should fit in a single page and contain all processes for their respective system parts.
Important
Most data-flow diagrams require a process-level depth layer for proper assessment.
When to use the process layer
Use the process layer for every system, especially if it handles sensitive data. Systems with sensitive data are at a higher risk of being breached. The context at this level helps you identify threats and ways to reduce or eliminate risks more efficiently.
Deep diving into a system part
In some cases, system parts may require more granular context because of their increased sensitivity and risk. You can best assess threats and risk-reduction strategies by going down to this layer. Follow the same rule from the system layer.
| Step | Guidance |
|---|---|
| 1 | Create a process element with a clear description label, such as Web Service Worker Name. |
| 2 | Create a new file and name it exactly the same way as the description label, with a path-like structure, such as Web Service Name - Web Service Worker Name. |
| 3 | Focus the data-flow diagram only on the system subpart you're "zooming into." |
The result is a series of data-flow diagrams in the subprocess layer, known as layer 2.
Tip
The path-like file naming structure helps you differentiate between the different levels.