IoT architecture

IoT architecture is the way a connected device is built in three layers of software: firmware on its own chip, an app on the owner's phone, and the maker's cloud that joins the two. Smart bulbs, fitness bands, air purifiers and connected cars are made in this way. IoT stands for the Internet of Things.

Here is how the layers work together in general. The firmware runs on the device and reads its sensors and controls its parts. The device connects to the owner's phone over Bluetooth or Wi-Fi, mainly for first set-up. The app on the phone shows the device's state and sends the owner's commands. The cloud sits in a data centre. It stores the device's data, knows which device belongs to which owner, and sends commands to the device when the owner is away from home. The maker also sends firmware updates from the cloud.

The cloud is in the middle because the phone and the device often cannot reach each other directly. When the owner is away, the phone is on a mobile network and the device is behind a home router, which blocks connections coming in from outside. So the device keeps a connection open to the cloud, and the cloud passes the commands along. The cloud also holds each device's identity and keys, so that only the real owner can control it and only the maker's signed updates are accepted. If the maker closes the cloud, the device may lose its remote features.

Take, for example, a smart air purifier. The owner sits in an office and taps the app to switch it on. The app sends the command to the cloud, the cloud passes it to the purifier at home, and the purifier's firmware starts the fan. Consider a fitness band that keeps readings, which the app collects over Bluetooth and uploads to the cloud for charts. Imagine a connected car, where the cloud also sends updates; see connected-vehicle clouds.

The layers appear on pages such as the connected home, connected appliances, smart lighting and IoT wireless chips. The standards that let devices from different makers work together are described in connectivity standards, and industrial IoT uses a similar plan for factories.

How is it different from a device that is not connected? An ordinary device works alone. A connected device needs all three layers, so it stops working fully if the maker closes the cloud.