Overview of IoT
The advancement of technology has seen the increased connection of things and devices, allowing for monitoring and automation of various activities. The Internet of Things (IoT) is one technology driving the interconnection of physical objects to the Internet, and the industry is expanding due to the growing demand for efficiency and automation. IoT combines embedded systems, wireless sensor networks, control systems, and automation, enabling connected industrial factories, smart cities and homes, smart retail, smart healthcare, and wearables. In order to function as a single stack, IoT devices have to connect and interact with one another. Such devices can only connect via built-in capabilities or gateways. Depending on the nature of the IoT device, its function, and end users, it is possible to determine the proper connectivity to use as part of the deployed IoT protocol.
What is an IoT Protocol?
Since IoT devices are connected to the Internet, they must follow the rules or standards governing how data and information are shared to the Internet. IoT protocols are similar to the protocols used for accessing the conventional Internet. As such, just like accessing information from a website through a browser requires protocols such as HTTP and others, IoT devices require protocols to communicate with each other. An IoT protocol is a set of standards that allow the exchange of data and information between distinct devices or machines within a given network. Within a given IoT network, IoT devices exchange information between them via a IoT protocols. IoT protocols guarantee that another device, a service, or a gateway reads and comprehends a device or sensor data. There are a variety of IoT protocols designed for different uses within the IoT tech stack.
Examples of IoT Protocols
Different layers require different IoT protocols to enable communication. The architecture layer the data passes through determines what IoT protocol is needed. Within the IoT system architecture, every IoT protocol allows communication between devices, between a device and a gateway, between a gateway and a data center, between a gateway and cloud, as well as between data centers. Below is an outline of the various IoT protocols based on IoT system architecture layers.
Application layer
This layer acts as the interface between the user and the device within a particular IoT protocol. For the application layer, the IoT protocols used include Data Distribution Service (DDS), Message Queue Telemetry Transport (MQTT), Constrained Application Protocol (CoAP), and Advanced Message Queueing Protocol (AMQP).
Data Distribution Service (DDS)
The DDS protocol is designed for real-time machine-to-machine communication, enabling scalability, reliability, better performance, and interoperability between connected devices regardless of the hardware or software platform. This versatile peer-to-peer protocol runs tiny devices and links high-performance networks.
Message Queue Telemetry Transport (MQTT)
MQTT uses the publisher-subscriber model and is ideal for small devices requiring efficient bandwidth and battery use. This messaging protocol is primarily designed for lightweight M2M communication and low-bandwidth connections to remote locations. This is the most widely adopted standard in the Industrial Internet of Things.
Advanced Message Queuing Protocol (AMQP)
Based on the request-response messaging or the publisher-subscriber model, this protocol establishes interoperability between messaging middleware, enabling various systems and applications to cooperate, generating standardized messaging within an industrial range. AMQP is a feasible protocol for end-to-end applications such as industrial heavy equipment systems with a more powerful network and devices.
Constrained Application Protocol (CoAP)
CoAP is designed to address the needs of HTTP-based IoT systems and thus is dependent on the User Datagram Protocol for securing communication between endpoints. This protocol is ideal for wireless networks often deployed for machine-to-machine environments with limited resources.
Transport layer
For any IoT protocol, the transport layer provides secure data communication between the layers. The layer’s fundamental protocols are Transmission Control protocols (TCP) and User Datagram Protocol (UDP).
Transmission Control Protocol (TCP)
TCP is the most used protocol for internet connectivity. This protocol provides host-to-host communication, divides large data sets into smaller packets, resends and reassembles data packets as necessary.
User Datagram Protocol (UDP)
UDP is a communication protocol allowing exchange of information between processes, thus enhancing data transmission rates compared to TCP. As such, UDP is ideal for applications that demand lossless data transmissions.
Network layer
An IoT protocol’s network layer enables direct devices-to-router communication. Examples of the protocols involved are IP and 6LoWPAN.
IP
IPv4 and IPv6 are the network layer’s two most used IP versions. IPv6 routes traffic across the Internet, identifying and locating devices within the network.
6LoWPAN
This IoT protocol is appropriate for low-power devices with limited processing power.
Data link layer
This layer is responsible for data transfer within the system’s architecture, detecting and correcting any errors found in the physical layer. The data link layer makes use of protocols such as LPWAN and IEEE 802.15.4.
Low-power wide-area networks (LPWAN)
Designed for communication across distances of up to 10km radius.
IEEE 802.15.4
Used with various standards such as ZigBee and 6LoWPAN to create wireless embedded networks. It is designed for low-powered wireless connection.
Physical layer
This is the communication channel between IoT devices within a particular environment. Examples of communication protocols used in this layer include ZigBee, Z-Wave, Wi-Fi/802.11, Radio Frequency Identification (RFID), Power Line Communication (PLC), Long-term Evolution (LTE), Near field Communication (NFC), and Bluetooth Low Energy (BLE).
Long-term Evolution (LTE)
LTE is designed for mobile devices and data terminals. This wireless broadband communication standard significantly increases a wireless network’s capacity and speed, supporting multicast and broadcast streams.
Bluetooth Low Energy (BLE)
BLE is widely used in consumer electronics due to its low cost and power consumption. This technology enables wireless connection of various electronic devices such as computers, printers, headsets, and telephones.
Near field communication (NFC)
This communication protocol makes use of the electromagnetic fields concept to allow two devices to exchange information within a four-centimeter range. NFC-enabled devices are primarily used for contactless mobile payments, smart cards, and ticketing.
Power Line Communication (PLC)
This communication technology allows data exchange over existing power cables, enabling powering and controlling an IoT device using the same cable.
Z-Wave
Uses low-energy radio waves to enable communication between two appliances.
ZigBee
ZigBee is based on IEEE 802.15.4 specifications and supports high-level communication protocols for creating personal area networks using small, low-power digital radios.
Conclusion
Numerous IoT protocols are currently supported by the Internet of Things, especially in light of the emergence of new IoT applications and use cases. As such, IoT protocols for other purposes will continue to emerge as the industry grows and evolves. Depending on the requirements of an IoT project, ease of use and reliability of the given protocol are important considerations. For instance, MQTT is suitable for low-bandwidth, remote location connections, given it is more centralized. As the IoT industry continues to advance, radical changes are expected in how devices communicate with each other. This is more likely to increase the adoption and significance of IoT protocols as the number of connected devices also rises. Organizations have the huge task of deciding on a suitable IoT protocol for their projects.
Additional Resources
References
Harikishnan., H. (2017). A Cyber-Physical Systems Approach to IoT Standards. https://www.iotforall.com/cyber-physical-systems-approach-iot?ss360SearchTerm=iot%20protocols
IoT Analytics. (2022). 5 Things to Know About IoT Protocols. https://www.iotforall.com/5-things-to-know-about-iot-protocols?ss360SearchTerm=iot%20protocols
Microsoft Azure. (2022). IoT Technologies and Protocols.https://azure.microsoft.com/en-us/solutions/iot/iot-technology-protocols
