MQTT (Message Queue Telemetry Transport) is a communication protocol that has been developed especially for M2M (Machine-to-Machine) communication and has become increasingly important in the context of the Internet of Things (IoT).

It is characterized by the following properties:

  • It enables simple networking of devices with few resources, such as sensors

  • It offers various service qualities (Quality of service), which ensures data transmission even in unstable networks

  • Metainformation is stored on the server side so that it does not have to be sent again after a connection has been interrupted and re-established

  • It enables the transfer of different data types without defining a defined structure

Functional principle

MQTT is based on an event-driven publish/subscribe architecture. The core is a central server (broker) to which both sender and receiver connect. The data is sent (published) or received (subscribed) via so-called topics. Topics are quasi communication channels into which transmitters, e.g. sensors, write their data. The broker checks which receivers (clients) have opened a channel for this data and forwards the data to the clients.

Concerning ibaPDA, this means that ibaPDA is positioned as an MQTT client that can send data to the MQTT broker and receive data from the MQTT broker.

As a client ibaPDA subscribes to all topics with the measured values that are to be acquired and made available via the MQTT broker. These can be, for example, data from higher-level systems of levels 2 and 3 or from sensors that publish their measured values via MQTT.

Via the outputs of the MQTT interface, ibaPDA can send data to the MQTT broker