Top 5 reasons MQTT is good for Industrial Systems
Why it works well as an IIoT edge protocol
As industrial operations become more connected, engineers need a reliable way to move data from remote devices to central locations quickly and efficiently. That’s what MQTT was designed for, and it does it well.
MQTT (Message Queuing Telemetry Transport) is a lightweight messaging protocol built for fast, efficient, and secure machine-to-machine communication. Originally developed for oil and gas telemetry, it’s now widely used as the first step in many IIoT (Industrial Internet of Things) applications.
Here are five reasons why:
1. MQTT keeps data flowing over unreliable or limited-bandwidth networks
MQTT is lightweight, designed for minimal resource use. It can continue sending and receiving data despite these obstacles:
- Low bandwidth connections
- High latency or packet loss
- Unstable or intermittent networks
2. A publish/subscribe model enables real-time, event-driven communication
MQTT eliminates the need for constant polling. When data changes it’s delivered instantly. This makes MQTT ideal for:
- Sending field device updates to HMIs and SCADA systems
- Asset and fleet tracking with live alerts
- Remote infrastructure monitoring (pumps, turbines, wellheads)
- Cellular/satellite-connected devices
- Battery-powered sensors and controllers
3. MQTT scales easily to thousands of devices
A single MQTT broker can handle thousands of simultaneous device connections, allowing architectures to grow horizontally as needed.
4. MQTT supports multiple payload types
By design, MQTT is just a transport layer. It specifies how messages get delivered, not what is inside. This allows MQTT to support multiple payload types (JSON, binary, Sparkplug, and more). Typically each type of device has its own message format that must be translated or standardized to be understood by others. A smart MQTT broker like the DataHub MQTT Smart Broker is able to do this translation and standardization of messages, making it easy to integrate the data from multiple payload types.
5. Built-In security
The publish/subscribe design of MQTT allows devices to make outbound connections through firewalls. This is a key factor in securing an industrial system for IIoT applications. Most industrial protocols have a client/server design where the client initiates the connection. If that client is outside the OT network, a firewall must be opened into the plant network to allow the connection. An MQTT device connects outbound, requiring no open inbound firewall ports.
In addition, MQTT supports TLS encryption, username/password authentication, X.509 client certificate authentication, and topic-level access control lists (ACLs).
Why just the edge?
MQTT was designed and implemented a decade before the IoT was even a concept. It is a lightweight protocol created to connect remote devices to a central location, and was never intended to serve as an IoT backbone. Plant-level and enterprise-level Industrial IoT applications require support for multiple-hop networking to pass data from device to plant to DMZ to IT to cloud. The MQTT Quality of Service guarantees are fragile across multiple connections, and it does not handle data overloads well. For these reasons MQTT cannot guarantee consistency of data across multiple connections, just quality of service over a simple, one-hop, device-to-broker link.
Summary: What Is MQTT Good For?
MQTT is a good edge protocol. It is lightweight, built for transporting real-time sensor and actuator data. For connecting devices at the edge to a plant or other central location, MQTT shines. But it would not be wise to rely on it as an enterprise-wide solution. It was not designed for large, complex Industrial IoT applications that require guaranteed consistency of data from the source to SCADA and HMIs, then through multiple hops and DMZs to IT and AI systems. MQTT provides a quick and secure way to move data from edge devices to a central location, where a more robust IoT backbone protocol like DHTP can deliver it throughout the enterprise.
