infoTECH Feature

May 17, 2023

Why Is MQTT Critical for the Industrial IoT?

What Is the Industrial Internet of Things (IIoT)?

The Industrial Internet of Things (IIoT) refers to the integration of connected devices, sensors, and advanced analytics in industrial environments to improve efficiency, productivity, and decision-making.

IIoT plays a crucial role in various aspects of industry operations, including predictive maintenance, enhanced field services, asset tracking, and energy management. In manufacturing, specifically, IIoT is especially promising for manufacturing, where it provides better traceability for supply chain management, quality control, and sustainability.

The idea behind IIoT is that intelligent machines and fast analytics capabilities are required to make use of the data produced by dumb machines. It aims to create a connected, intelligent industrial ecosystem that leverages data-driven insights to optimize operations, enhance productivity, and drive innovation. By interconnecting devices, sensors, and analytics, IIoT fosters collaboration and real-time decision-making, leading to greater efficiency, sustainability, and competitiveness in the industry.

What Is MQTT?

MQTT (Message Queuing Telemetry Transport) is a lightweight, open-source, publish-subscribe messaging protocol designed for constrained environments and low-bandwidth, high-latency, or unreliable networks. Developed by IBM (News - Alert) in 1999, MQTT has become the de facto standard for communication in IoT and IIoT applications due to its efficient use of resources and ease of implementation.

MQTT operates over TCP/IP and uses a broker-based architecture, where devices (clients) exchange messages through a centralized server (broker). Clients can publish messages to a specific topic, while other clients can subscribe to receive updates on that topic. This efficient messaging system allows for real-time communication and reduced network load, making MQTT ideal for IoT applications.

How Does MQTT Work?

MQTT operates using a pub/sub communication model, which is based on the exchange of messages between clients through a centralized server called a broker. This model allows for efficient, real-time communication and scalability in IoT and IIoT applications.

In the pub/sub model, clients can either publish or subscribe to messages. Publishing involves clients sending messages to a specific topic, and subscribing entails clients receiving messages on topics they have expressed interest in. The broker acts as an intermediary, receiving messages from publishers and distributing them to the appropriate subscribers.

When a client wants to publish a message, it sends the message to the broker, specifying the topic and quality of service (QoS) level. QoS levels dictate the delivery guarantee for messages, ranging from at-most-once (QoS 0) to exactly-once (QoS 2). The broker then checks the list of subscribers for the given topic and forwards the message accordingly.

If a subscribing client's connection to the broker is broken, the broker can handle the situation based on the client's "Last Will and Testament" (LWT) message and the QoS level. The LWT message is predefined by the client during the initial connection and is sent by the broker to specified recipients upon detecting an unexpected disconnection. Additionally, the broker can store undelivered messages with QoS levels 1 or 2 for the disconnected client, and once the client reconnects, these messages are transmitted to ensure reliable communication.

8 Reasons MQTT Is Critical for the Industrial IoT

MQTT has become a critical technology for the IIoT due to its ability to facilitate communication between devices, applications, and servers in various industrial settings. Here are some reasons why MQTT is crucial for the Industrial IoT:

  1. Scalability: Industrial IoT deployments often involve a large number of connected devices, sensors, and machines that need to communicate with each other and with centralized systems. MQTT is designed to handle a high volume of messages from numerous devices with minimal overhead, making it an ideal solution for managing communication in large-scale IIoT systems.
  2. Efficiency: MQTT uses a publish-subscribe model, which means that devices only send messages to a central broker, and the broker then distributes the messages to relevant subscribers. This model reduces the need for devices to maintain individual connections with each other, which can save significant bandwidth and processing resources in large-scale deployments.
  3. Low bandwidth requirements: MQTT's lightweight nature makes it well-suited for environments with limited bandwidth, such as remote industrial sites or areas with poor network connectivity. MQTT uses compact message headers and supports message compression, enabling efficient data transmission even in low-bandwidth conditions.
  4. Robustness in unreliable networks: Industrial environments can be challenging for communication protocols due to the presence of network latency, packet loss, or intermittent connectivity. MQTT is designed to handle such conditions by implementing a quality of service (QoS) mechanism that ensures message delivery with varying degrees of reliability, depending on the application requirements.
  5. Ease of implementation and integration: MQTT is relatively easy to implement on various devices and platforms, as it requires minimal processing power and memory resources. Its simplicity makes it compatible with a wide range of hardware and software, facilitating seamless integration into existing IIoT systems.
  6. Real-time data exchange: Industrial IoT applications often require real-time communication between devices, sensors, and control systems to monitor and manage operations effectively. MQTT's low-latency message delivery enables real-time data exchange, allowing timely decision-making and operational adjustments based on the latest information.
  7. Security: Although MQTT does not inherently provide end-to-end encryption, it can be used with Transport Layer Security (TLS) to secure communications between devices, brokers, and subscribers. This added layer of security helps protect sensitive data and prevent unauthorized access to industrial systems.
  8. Interoperability: MQTT's standardized protocol and wide adoption in the IIoT domain make it an ideal choice for enabling interoperability between different devices, applications, and platforms. By using a common messaging protocol, industrial organizations can more easily integrate diverse systems and share data across various components of their IIoT infrastructure.

By adopting MQTT, industrial organizations can improve the interoperability, efficiency, and reliability of their IIoT systems, ultimately enhancing their overall operational performance.


In conclusion, MQTT's lightweight design, scalability, efficiency, and robustness make it a critical communication protocol for the Industrial IoT. Its ability to function effectively in low-bandwidth and high-latency environments, coupled with real-time data exchange capabilities, ensures that it meets the unique demands of industrial applications.

Furthermore, its ease of implementation, integration, and interoperability, along with robust security measures, enables seamless collaboration and analytics in interconnected industrial ecosystems. As IIoT continues to transform industries and enhance productivity, MQTT's role as a cornerstone for reliable, efficient, and secure communication cannot be overstated.


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