But how does Bluetooth Mesh work?
Bluetooth Mesh uses a so-called "managed flood message relay" procedure. This means that all participants in the network - the nodes - receive the same message and can also forward it. This makes it possible to reach several thousand participants and at the same time guarantee a high performance and reliability of the network.
The process can be compared to messaging services from social media. All nodes can send messages to the network ("publish") and subscribe to messages ("subscribe"). All nodes in a group that are interested in the status of the light value, for example, can subscribe to these messages. Sensors, switches and luminaires communicate directly with each other. The concept of decentralisation eliminates the need for a central control unit, which means that even if one or more nodes fail, the lighting control continues to function.
The efficient data transmission with Bluetooth Mesh reduces the load on the radio network and guarantees high reliability. The size of the so-called payload of the messages to be transmitted is optimised to generate as little radio traffic as possible within the network. For example, if you want to set the light level, it is sufficient to send the command "Light Lightness Set" (2 bytes), the "Lightness Level" (2 bytes) and a "Transaction Identifier" (1 byte: new message or new transmission). If you want to set the lightness level to the maximum, the message is: 0x82 4C FF FF 00.