IoT devices require connectivity to truly make them the “Internet of Things.” Different communication protocols exist to enable devices to receive and send data from one endpoint to the next, whether that is directly to the cloud, an application, or another device. Each IoT protocol has its advantages and disadvantages, so while one IoT protocol may work better for one IoT scenario, it might not work for the next.
Consider the different layers of the IoT network in which data must travel as shown in the OSI model diagram below (e.g. application layer, network layer, physical layer). The many IoT protocols to choose from depend on the range and how the data travels between different IoT endpoints, or between devices themselves, device-to-gateway, device-to-cloud, device-to-data center communication, or a combination of these communications. However, it is important to note that the OSI model is simply a model, and some lines are blurred for non-OSI protocols.
OSI Layer
This blog will define the core characteristics of common IoT communication protocols and highlight IoT scenarios within different industries where they may be most applicable.
1. Ethernet
Even in the age of wireless technologies, Ethernet still has many applications in IoT. Based on the IEEE 802.3 standard, Ethernet provides a wired communication to connect IoT devices to the internet. Ethernet is considered the leading network protocol in LAN applications and can provide data transfer rates as high as 100 Mbps. These characteristics make Ethernet a suitable communication protocol for stationary or fixed IoT devices.
Since fixed IoT devices are in close range to one another, Ethernet promises low latency and fast data speeds. One example is sensor units installed within a building automation system, such as those used for monitoring temperature and humidity, which can use wired networking technologies like Ethernet rather than a wireless communication like Wi-Fi for a faster, more reliable, and secure connection.
While Ethernet has its own limitations related to limited mobility, infrastructure and set up requirements, it is nevertheless growing in popularity among transportation, automotive, and industrial applications, thanks to emerging cabling strategies and variations of the IEEE 802.3 standard. For example, while different communications protocols enable connected cars to communicate with systems in other vehicles, Ethernet can work to help connected car systems to effectively communicate with the different systems within the car itself, such as diagnostic and radar sensors.
2. MQTT
MQTT (Message Queuing Telemetry Transport) is described as a “lightweight” messaging protocol that collects data from various devices that run over the TCP (Transmission Control Protocol). It is one of the most preferred communication protocols for IoT devices because as a publish/subscribe messaging protocol, it is designed for networks that are unreliable and have low bandwidth and high latency. Therefore, alongside its low processing power, MQTT’s lightweight protocol is well suited for small, cheap, lower-powered IoT devices.
MQTT has been famously used for Facebook’s Messenger app because the MQTT protocol conserves battery power during mobile phone-to-phone messaging. However, beyond this, MQTT has also proved to work extremely well for IoT applications that conduct remote monitoring; the MQTT protocol allows high volumes of sensor messages to be sent to analytics platforms. MQTT serves as the go-to solution for machine-to-machine (M2M) communications when transmitting data to not just analytics platforms but also servers and dashboards. One real-world example is IoT-based sensors, such as fire detectors, that want to send real-time messaging alerts to various devices.
3. RFID/NFC
Near Field Communication (NFC) is based on Radio Frequency Identity (RFID) technology, a communication method used for tracking and identifying objects wirelessly. NFC-enabled devices are embedded with a small chip that becomes activated when in close contact with another NFC chip, thereby enabling a simple and secure two-way interaction between electronic devices. It is considered a short-range low data rate wireless communication.
NFC has been most notably used in the payments market to help facilitate contactless transactions. However, it has now been widely adopted in mobiles devices and IoT devices. For example, NFC has seen successful results in the smart home and has proved especially helpful when users have IoT devices that don’t have a user interface, such as light bulbs, sensors, and other small appliances. This is because NFC allows devices to pair even when they use different communications technologies. So, a smart appliance can be added to the network or join a Wi-Fi network without manually having to enter a serial number or unique passcode.
NFC’s ability to bring IoT to unpowered objects is just one benefit that can move IoT toward more wide-scale adoption. NFC also offers an easy way for devices to connect with just a tap and allows end users to be more in control of their IoT appliances.
4. LTE Cat M1
LTE Cat-M1 is based on Low Power Wide Area (LPWA) technologies and operates using existing LTE cellular networks to provide a two-way data transmission. It specializes in transferring low to medium amounts of data (typically between 200 to 400 kbps). Additionally, LTE Cat-M1 is able to connect resource-constrained devices to the internet that transmit small amounts of data over long periods of time, “while providing high signal penetration and retaining a minimal power consumption.” These characteristics make it ideal for IoT devices that are power-constrained, thus offering an energy efficient solution for smart industry users. For example, when only small amounts of data transferred is required, LTE Cat-M1 can be used for smart metering, including sensors that periodically need to report readings such as temperature, air quality, and humidity.
LTE Cat-M1 also cuts costs. For one, since the frequency in which batteries need to be replaced is drastically lowered, any costly downtime is significantly reduced. Additionally, its reliance on existing LTE infrastructure eliminates the need to build additional infrastructure.
5. LoRaWAN
LoRaWAN is a type of low-power wide-area network (LPWAN) technology, a wireless communication network that allows connected devices to have long-range communications capabilities with a low bit data rate. More specifically, the LoRa in LoRaWAN (short for “long range”) means it uses RF signals to communicate (LoRa radio modulation). LoRaWAN uses radio waves to communicate with LoRaWAN gateways to provide functions like encryption and identification.
A typical use case for LoRa is in smart cities, where low-powered and inexpensive IoT devices (typically sensors or monitors) are spread across a large area. They can send small packets of data to a central administrator to provide different smart solutions like a smart building solution that tracks building systems and optimizes occupancy through monitoring.
LoRaWAN is also beneficial to supply chain and logistics companies to track high-value assets, even those in transit. For example, IoT-based fleet tracking solutions that use a LoRaWAN connection can offer cost savings by allowing fleets to stay on the road for longer, improve fuel economy, increase safety, offer visibility into maintenance concerns, and improve overall operational efficiency.
6. Modbus
Modbus is an open data communications protocol that enables data communication between various servers and clients on different devices and networks. Since it is also an open-source protocol, it can be used freely by all. However, most of its applications have been in the area of IIoT (Industrial IoT). It has been widely used in factory automation to connect industrial electronic devices with other automation equipment.
Since Modbus uses a simple Master/Slave communication mechanism, it offers the simplicity needed for communication between smart devices and sensors to monitor field devices using standard PCs and Human-machine interfaces. The easy transfer of data for automation is possible (i.e. sensor data to the automation device) with Modbus because data can be transferred via a single layer, which is easier to do when compared to other protocols.
Another benefit offered by Modbus is the ease with which multiple devices can be integrated on the same network, allowing different types to communicate with other devices. So, it also offers a cost-effective way for old equipment and new equipment to communicate. This advantage and Modbus’ simplicity and open availability of many devices allow for various applications in different industries like oil and gas.
Each IoT communication protocol has its strengths and weaknesses in terms of coverage (i.e. range), scalability, cost, and network requirements. Stay tuned for more updates on specific IoT Use Cases!
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About the Author: Karen is a passionate B2B technology blogger. While studying at Georgia Tech, Karen first grew interested in cybersecurity and has since worked for several security and cloud companies as a global marketer. When she’s not freelance writing, Karen loves to explore new food trends.
