What Is MQTT
MQTT is a lightweight publish/subscribe messaging protocol originally developed by IBM for satellite telemetry and standardized by OASIS. It was designed to operate reliably over low-bandwidth, high-latency, or unreliable networks — characteristics common in remote industrial sites, cellular-connected IoT devices, and edge computing environments.
In MQTT, devices (publishers) send data to a central broker on named topics. Subscribing systems — like an IIoT monitoring platform — receive all messages published to topics they have subscribed to. The broker handles routing between publishers and subscribers.
MQTT is used in:
- Industrial IoT sensor networks (environmental monitoring, predictive maintenance sensors)
- Edge gateway telemetry from remote and unmanned sites
- Telecom tower monitoring and remote infrastructure management
- Renewable energy asset monitoring (solar, wind)
- Smart building IoT overlay systems
- Industrial equipment with embedded IoT connectivity
- Machine-to-machine communication in Industry 4.0 environments
MQTT Protocol Variants and Standards
| Variant | Description | Typical Use |
|---|---|---|
| MQTT 3.1.1 | Widely supported stable version | The dominant version across IoT devices and brokers |
| MQTT 5 | Enhanced version with improved error handling, session expiry, topic aliases | Modern implementations, enterprise deployments |
| Sparkplug B | MQTT + defined topic namespace + structured payload format (Protobuf) | Industrial IoT, SCADA over MQTT, IIoT interoperability |
Sparkplug B is particularly important for industrial monitoring. Developed by Cirrus Link and now managed by the Eclipse Foundation, Sparkplug B defines a standardized topic namespace and data encoding on top of MQTT, enabling SCADA and IIoT platforms to interoperate with MQTT-enabled industrial devices using a consistent data model.
MQTT Quality of Service Levels
MQTT defines three Quality of Service (QoS) levels that control message delivery guarantees:
| QoS Level | Delivery Guarantee | Use When |
|---|---|---|
| QoS 0 | At most once (fire and forget) | Frequent sensor readings where occasional loss is acceptable |
| QoS 1 | At least once (acknowledged) | Alarm events, configuration changes where delivery matters |
| QoS 2 | Exactly once (fully acknowledged) | Critical events where duplicate delivery must be avoided |
Mango by Radix IoT supports all three QoS levels.
Industries That Use MQTT
Telecom
Telecom operators use MQTT extensively for remote tower monitoring — reporting generator status, battery levels, cooling, environmental conditions, and equipment alarms from thousands of distributed sites. MQTT’s lightweight protocol is well-suited to cellular-connected remote assets with limited bandwidth.
Renewable Energy
Modern solar inverters, weather stations, and energy storage systems increasingly support MQTT in addition to or instead of Modbus. MQTT enables real-time telemetry from distributed renewable energy assets to centralized monitoring systems.
Industrial IoT
Modern industrial equipment with embedded IoT connectivity often uses MQTT to publish operational data. Predictive maintenance sensors, condition monitoring devices, and IoT-enabled PLCs use MQTT to communicate without the polling overhead of traditional industrial protocols.
Smart Buildings
IoT overlay systems for commercial buildings — occupancy sensors, indoor air quality monitors, energy sub-meters with IoT connectivity — publish data via MQTT alongside or instead of traditional BACnet.
Edge Computing
Edge gateways that aggregate data from field devices (Modbus, BACnet, serial instruments) and translate it for cloud or central monitoring systems commonly use MQTT as the northbound communication protocol to the central platform.
How Mango by Radix IoT Implements MQTT
All protocol drivers, including the MQTT driver, are included in a standard Mango by Radix IoT installation and covered by the license. There are no separate driver purchases, per-protocol licenses, or add-on fees. Mango by Radix IoT includes a native MQTT driver that subscribes to topics on an MQTT broker and processes incoming messages as monitored data points.
MQTT Broker Connectivity
Mango by Radix IoT connects to any MQTT broker — HiveMQ, EMQX, Mosquitto, AWS IoT Core, Azure IoT Hub, and others. Connection configuration includes broker address, port, authentication, and TLS/SSL certificate handling.
Topic Subscription
Mango by Radix IoT subscribes to MQTT topics and maps incoming payloads to data points in the Mango by Radix IoT historian. Wildcard topic subscriptions (using # and + patterns) enable subscribing to entire topic hierarchies from a single configuration entry.
Payload Parsing
Mango by Radix IoT supports common MQTT payload formats including JSON, plain numeric values, CSV, and Sparkplug B Protobuf payloads. Custom scripting enables parsing of non-standard payload formats.
Sparkplug B Support
For industrial MQTT environments using Sparkplug B, Mango by Radix IoT processes NBIRTH, DBIRTH, NDATA, DDATA, NDEATH, and DDEATH messages in accordance with the Sparkplug B specification, enabling native interoperability with Sparkplug-compliant devices and edge nodes. Sparkplug B is delivered as a dedicated module, separate from the generic MQTT module.
Bidirectional Communication
In addition to subscribing to data, Mango by Radix IoT can publish MQTT messages to configured topics — enabling setpoint changes, command delivery, and integration with systems that consume MQTT output.
Use Cases: MQTT + Mango by Radix IoT
Telecom Tower Fleet Monitoring
A telecom operator connects thousands of remote tower sites to Mango by Radix IoT via MQTT. Each site’s edge gateway publishes generator fuel level, battery state, rectifier status, and environmental conditions to an MQTT broker. Mango by Radix IoT subscribes to all site topics, stores time-series data in the historian, and delivers alarm notifications to on-call network operations staff.
Renewable Energy Aggregation
A solar fleet operator’s string inverters publish generation data and fault codes via MQTT. Mango by Radix IoT subscribes, stores historical generation records, compares actual vs. modeled performance, and flags underperforming arrays for maintenance dispatch.
IIoT Edge Integration
Edge gateways at a manufacturing plant translate Modbus data from PLCs and sensors into MQTT messages. Mango by Radix IoT subscribes at the cloud or central-site level, providing enterprise-wide visibility into plant operations without direct IP connectivity to field devices.
Predictive Maintenance Sensors
Vibration, temperature, and current monitoring sensors installed on rotating equipment publish readings via MQTT. Mango by Radix IoT ingests this data, calculates derived metrics (FFT, trend slopes), and triggers predictive maintenance alerts when equipment condition degrades.