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    The MQTT protocol defines two types of network entities: a message broker and a number of clients. An MQTT broker is a server that receives all messages from the clients and then routes the messages to the appropriate destination clients.[17] An MQTT client is any device (from a micro controller up to a fully-fledged server) that runs an MQTT library and connects to an MQTT broker over a network.[18]

    Information is organized in a hierarchy of topics. When a publisher has a new item of data to distribute, it sends a control message with the data to the connected broker. The broker then distributes the information to any clients that have subscribed to that topic. The publisher does not need to have any data on the number or locations of subscribers, and subscribers, in turn, do not have to be configured with any data about the publishers.

    If a broker receives a message on a topic for which there are no current subscribers, the broker discards the message unless the publisher of the message designated the message as a retained message. A retained message is a normal MQTT message with the retained flag set to true. The broker stores the last retained message and the corresponding quality of service (QoS) for the selected topic. Each client that subscribes to a topic pattern that matches the topic of the retained message receives the retained message immediately after they subscribe. The broker stores only one retained message per topic.[19] This allows new subscribers to a topic to receive the most current value rather than waiting for the next update from a publisher.

    When a publishing client first connects to the broker, it can set up a default message to be sent to subscribers if the broker detects that the publishing client has unexpectedly disconnected from the broker.

    Clients only interact with a broker, but a system may contain several broker servers that exchange data based on their current subscribers’ topics.

    A minimal MQTT control message can be as little as two bytes of data. A control message can carry nearly 256 megabytes of data if needed. There are fourteen defined message types used to connect and disconnect a client from a broker, to publish data, to acknowledge receipt of data, and to supervise the connection between client and server.

    MQTT relies on the TCP protocol for data transmission. A variant, MQTT-SN, is used over other transports such as UDP or Bluetooth.

    MQTT sends connection credentials in plain text format and does not include any measures for security or authentication. This can be provided by using TLS to encrypt and protect the transferred information against interception, modification or forgery.

    The default unencrypted MQTT port is 1883. The encrypted port is 8883.[20]

    Monitoring Process Parameters via MQTT
    Process parameters such as speed (RPM), pressure, displacement, temperature, and time play a pivotal role in determining product quality. These parameters are regularly monitored and compared with predefined metrics on the server using pre-built algorithms. Predictive decisions are then formulated and sent back to the edge devices. HMIs are integrated with the MQTT Agent to relay small, time-sensitive data variations to the server for rapid decision-making. We anticipate the integration of MQTT Agents within more PLCs for streamlined data transmission.

    In conclusion, MQTT is a pivotal element in modern manufacturing, bridging the gap between IT and OT and enhancing Industry 4.0 implementations. Its lightweight design ensures machine availability and uptime by facilitating swift data exchange, keeping devices focused on data aggregation. Two-way communication with QoS 2 enables transactional process control, ensuring machines resume operations promptly. MQTT’s real-time data transfer supports edge efficiency and data aggregation, easing the computational load during large-scale deployments. Additionally, it plays a crucial role in monitoring and analyzing process parameters, enhancing product quality. In a mere 100 words, MQTT emerges as a vital catalyst for streamlined, efficient, and real-time manufacturing processes.

    The Matter home network protocol, formerly known as Project Connected Home over IP (Project CHIP), is designed to provide a standard for smart home devices to communicate with each other. Matter uses IP (Internet Protocol) as its foundation, allowing devices to connect and communicate over IP networks.

    While Matter itself is designed to work over IP, it doesn’t specify a particular transport protocol like MQTT (Message Queuing Telemetry Transport). Instead, Matter relies on IP-based protocols for communication. MQTT is a separate messaging protocol commonly used in the IoT (Internet of Things) space, but it is not the protocol specified by Matter.

    In summary, Matter primarily utilizes IP for communication within a home network and does not specifically rely on MQTT.

    2 years, 5 months ago