Offline but connected: How air-gapped IIoT devices stay up to date
Modern production and manufacturing thrive on the networking and digitisation of machines, sensors and systems. The Industrial Internet of Things (IIoT) is an indispensable part of this development. IIoT devices collect and process large amounts of data to enable efficiency gains, predictive maintenance and optimised operational processes.
IIoT devices are usually networked with each other and with the Internet to ensure continuous data exchange. However, there are scenarios in which an Internet connection is undesirable or impossible, whether for security reasons or due to geographical conditions. These air-gapped edge systems place special demands on data processing and require alternative solutions for updates and data transfers.
Air-gapped systems are networks or individual devices that are deliberately disconnected from the internet. These systems cannot therefore be updated in the conventional manner. The data they collect cannot simply be sent to the cloud for analysis. To overcome this challenge, an external transfer medium is required to store files for software updates.
The solution: smartphones as update bridges
The figure shows a solution concept for this special case of Industrial IoT.
Instead of a direct connection to the Internet, we rely on a mobile, flexible and secure bridge: an Android smartphone. With a specially developed app, it takes on the role of a data transmitter. The app downloads update files in the form of Docker images from the Azure Container Registry and stores them locally on the smartphone. The smartphone also serves as a storage medium for the IIoT device's data.
Wifi Direct is used as the data transfer method in this example. Wifi Direct offers high transfer rates and enables direct device-to-device communication between WLAN end devices. This technology is particularly suitable for air-gapped systems, as the devices involved do not require an Internet connection and a direct connection is possible. High data rates are important because the size of the update files can vary greatly depending on the container image.
The process in detail:
- Establishing a connection: For the software update, the smartphone is connected to the IIoT device via Wi-Fi Direct from the Android app. Appropriate Wi-Fi Protected Access (WPS) methods are used to establish a secure connection.
- Transferring the update files: Once a connection has been established, the update files that have already been downloaded can be sent to the IIoT device via the app. A specially developed system on the IIoT device receives these files and starts the update process.
- Data backup: In addition, the data generated by the IIoT device can be downloaded via the Android app and temporarily stored on the smartphone. This backed-up data is then available for further processing.
The developed solution and the technologies used have potential for a practical application scenario. With the increasing spread of IIoT, it can be assumed that solutions for air-gapped systems will play an increasingly important role in making industrial processes efficient, even in security-critical or remote areas. We support you in this.
