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MQTT-SN: The Smart Choice for IIoT

by Simon Johnson, Lee Stacey
14 min read

The smart factory has arrived and the IIoT (Industrial Internet of Things) landscape is continuing to expand at an accelerating pace. Projections estimate that the IIoT market size will reach $3.3 trillion by 2030, indicating billions of connected devices. This means the need for efficient and scalable IoT solutions becomes paramount. But how do we ensure these interconnected devices, often resource-constrained and sometimes battery-powered, can function seamlessly without draining their limited resources?

Enter MQTT-SN (MQTT for Sensor Networks), a lightweight publish and subscribe messaging protocol specifically designed for embedded devices on non-TCP/IP networks. It is an optimized sibling specification for MQTT versions 3.1.1 and MQTT 5.0, for use on low-power, constrained devices. In this blog post, we'll delve into the power-saving and scaling capabilities of MQTT-SN, exploring how it empowers the ever-growing world of industrial automation and data acquisition.

MQTT-SN: The Essential Low-Power Solution for IoT Scalability

Besides the obvious “less power = lower energy cost” equation, there are further benefits to reducing the power drain from IoT devices. Where sensors are placed all over factories and monitor remote equipment, ensuring efficient power usage becomes paramount for several reasons. Traditional wired connections and frequent battery replacements are not only cumbersome but also limit the scalability and flexibility of these deployments. The importance of reducing power consumption becomes especially evident in this context.

Imagine a vast network of sensors scattered across a large, multi-location production facility. Every sensor or connected device needs power, which can be costly at scale. In the case of remote devices requiring regular battery changes, the costs can be even higher due to the need for regular replacement.

Power reduction provides a solution. By minimizing the energy consumption of individual devices, the electricity bill is lower and reliance on frequent battery replacements diminishes. This translates to reduced maintenance needs, improved operational uptime, and significant cost savings.

Furthermore, power-efficient devices with extended battery life or the ability to harvest energy from their environment with solar or wind power, for example, open doors to a wider sensor distribution. Imagine sensors placed in crucial yet previously inaccessible areas, providing a more comprehensive view of industrial processes. This increased scalability of monitoring empowers data-driven decision-making and can help to optimize operations.

The environmental impact also deserves a mention. Limiting reliance on disposable batteries translates to a greener IIoT ecosystem. By combining low-power protocols like MQTT-SN with energy harvesting techniques, we move one step closer towards a sustainable future for the IIoT.

In essence, power reduction is of high importance in a robust and scalable IIoT solution. It ensures the feasibility of large-scale deployments, minimizes maintenance burdens, and paves the way for a more sustainable approach to industrial automation.


Firstly, MQTT-SN is built for efficiency. Compared to its parent protocol MQTT, the MQTT-SN architecture boasts a more compact design. Message headers are minimized, and topic names can be replaced with short topic IDs. This reduction in data size translates to less bandwidth consumption and lower processing requirements for resource-limited devices.

For further power reduction, MQTT-SN introduces a sleep mechanism. Devices can effectively switch off and receive queued messages upon switching back on. This significantly reduces power consumption, extending battery life for battery-powered sensors.

Like MQTT, MQTT-SN is built for scale, utilizing a publish/subscribe model. Devices publish data to specific topics, and interested subscribers receive only relevant information. This targeted approach minimizes unnecessary data transmission, optimizing network bandwidth usage. Multiple devices may communicate with the MQTT broker via an MQTT-SN gateway.

By addressing the critical aspects of power efficiency and scalability MQTT-SN paves the way for robust and reliable communication in IIoT environments. As the industrial landscape embraces automation and data-driven decision-making, MQTT-SN stands out as a powerful tool for driving innovation and ensuring seamless operation within the intelligent factory of the future.

For even more power saving and lower data overhead, MQTT-SN adds another QoS mode to those utilized by MQTT. QoS mode -1: allows for blind fire-and-forget messaging, meaning that the device can simply wake up and send a message without having to wait for a response.

Unlike MQTT, MQTT-SN doesn’t rely on a TCP/IP transport. Instead, it is designed to be agnostic of the underlying network services. As such, any network which supports a bi-directional transfer service between node and gateway should be able to support MQTT-SN.

MQTT-SN Limitations

There are some limitations to be aware of when choosing MQTT-SN as your messaging protocol. The elephant in the room here is security. While you can technically use any encryption you want, there is currently no security built into the MQTT-SN protocol itself. However, this issue will be addressed in the next revision of the standard.

In terms of complexity, learning, implementing and managing MQTT-SN can be difficult compared to some simpler protocols. However, we have experts who can help guide you through the learning curve.

Ensuring you use compliant tools and libraries designed specifically for MQTT-SN can also help simplify the process. While gateways enable communication between devices and the broker, ensuring compatibility between different MQTT-SN implementations and existing infrastructure is crucial. Choosing solutions that adhere to the latest MQTT-SN specifications and offer clear migration paths can help mitigate compatibility issues.

IIoT Use Cases for MQTT-SN

MQTT-SN's strengths in power efficiency, scalability, and lightweight design make it a suitable choice for various IIoT applications. Here are some typical use cases:

  • Wireless sensor networks: In industrial settings, numerous sensors monitor temperature, pressure, vibration, and other crucial parameters. MQTT-SN's low data footprint and sleep functionality are perfect for these battery-powered sensors, enabling them to transmit data efficiently while conserving battery life.

  • Smart building management: Buildings are increasingly integrated with sensors for monitoring energy consumption, occupancy, and environmental conditions. MQTT-SN facilitates efficient communication between these sensors and central control systems, enabling real-time data collection and optimized building operations.

  • Predictive maintenance: By continuously monitoring equipment health data (vibration, temperature), MQTT-SN allows for early detection of potential issues. This enables preventative maintenance actions, reducing downtime and associated costs.

  • Industrial asset tracking: Tracking the location and status of critical assets like tools, machinery, or inventory within a large facility is crucial. MQTT-SN's ability to handle data from low-powered RFID tags or GNSS trackers makes it suitable for such applications.

  • Remote monitoring and control: In applications like oil and gas pipelines or environmental monitoring stations in remote locations, MQTT-SN enables efficient communication with battery-powered sensors, allowing for real-time data acquisition and remote control capabilities.

Additional factors supporting these use cases:

  • Scalability: MQTT-SN efficiently handles data from a large number of devices due to its publish/subscribe model, making it suitable for large-scale deployments.

  • Integration: MQTT-SN can seamlessly integrate with existing infrastructure through gateways, enabling data exchange with cloud platforms or other industrial control systems.

The Future of MQTT-SN

As members of the OASIS MQTT Technical Committee and Chair of the MQTT-SN Subcommittee, building upon the learnings of the MQTT-SN Version 1.2 protocol specification, the HiveMQ team is leading the development of the MQTT-SN 2.0 standard. By actively contributing to the development of MQTT-SN v2.0, HiveMQ aims to shape the next generation of the protocol. Future development of the protocol will see enhanced efficiency, such as further optimizations for memory usage and power consumption crucial for devices with limited resources and built-in quantum-safe security mechanisms. In essence, HiveMQ draws on its expertise with the existing protocol to pave the way for a more robust and future-proof MQTT-SN v2.0.

In Conclusion

MQTT-SN presents a compelling solution for IIoT applications. Its lightweight design, efficient communication model, and emphasis on power conservation make it ideal for resource-constrained devices prevalent in industrial settings. As the IIoT landscape continues to evolve, MQTT-SN is poised to play a vital role in facilitating the scalable exchange of data, ultimately empowering the next generation of industrial automation.

Explore HiveMQ Edge,  the edge-optimized, fully standards-compliant MQTT broker that incorporates MQTT-SN protocol for constrained devices.

View HiveMQ Edge

Simon Johnson

Simon Johnson is a Principal Engineer at HiveMQ with over 18 years of experience at the cutting edge of the IoT, spearheading many successful enterprise projects. Simon is a co-chairman of the OASIS MQTT-SN technical committee, having built a low-power, low-cost, ubiquitous MQTT network over 2G, 3G, 4G, Cat-M1, and LoRaWAN.

  • Simon Johnson on LinkedIn

Lee Stacey

Lee Stacey is an IoT enthusiast and former engineer with 15 years of experience in technology marketing. Over the years, Lee has partnered with numerous engineering and technology brands to cultivate vibrant communities and create engaging, valuable content for engineers and makers.

  • Contact Lee Stacey via e-mail
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