The infrastructure layer isn't so much an actual layer between software and hardware, but more of the physical and mechanical structure of the fog node. As fog devices will be in harsh and remote locations, they must be rugged and resilient as well as self-reliant. OpenFog defines the cases that need to be considered in a fog deployment, including:

• Size, power, and weight characteristics
• Cooling systems
• Mechanical support and retention
• Serviceability mechanics
• Physical attack resistance and reporting