A Comprehensive Guide to IoT Messaging Protocols

Take a moment and look around yourself. You are surrounded by technology and smart devices that make your life easier every day, from your professional life to personal. With the technological revolution, the use of the Internet of Things is also increasing where people are using connected devices to keep track of their health, city traffic, automate business operations, control home appliances, and whatnot. Almost every person owns smart devices, such as wearables, smartphones, appliances, automobiles that can be connected to the internet to exchange information and data. When we talk about connecting devices to the internet, there are 2 ways to do that. They can either use gateway or can have inbuilt network capability.

The most interesting point is that IoT devices use messaging and communication protocols at different layers to establish a connection with the internet. These IoT messaging protocols are used to transmit messages from IoT devices to the broker or IoT messaging hub. The selection of the protocol depends mainly on the type, function, and layer to be performed by the device.

IoT Messaging Application Protocol

As we said, IoT protocols are used to transmit messages or telemetry from IoT devices to IoT messaging hub. The protocols can operate over TCP and higher-level abstractions like HTTPs. To connect IoT devices to the internet or even with each other, methods, such as WiFi, Bluetooth, Cellular, LoRaWAN, ZigBee, etc., are used. Once the components are connected, a messaging protocol will be used to send messages to and from devices.

In this blog, we will understand different IoT protocols used across industries. So, let’s get started:

MQTT (Message Queue Telemetry Transport)

MQTT is a lightweight publish-subscribe-based network protocol used to communicate data to the servers. It is a machine-to-machine protocol that transports telemetry between IoT devices with a primary purpose to manage the devices remotely. If a huge network of small devices is to be monitored, then this is the best option as it manages the devices via the internet, such as underwater lines, parking sensors, energy grid, and more. It runs typically over TCP/IP but can operate on top of other IoT protocols if they provide lossless, ordered, bi-directional connections. It is ideal for the devices with limited bandwidth or that have other constraints and require remote devices with small code footprints. The MQTT messages are sent asynchronously through publish-subscribe architecture where messages are encapsulated in defined control packets.

Features

• Lightweight, hence great for constrained networks
• Supports publish-subscribe messaging
• Low power usage
• Minimized data packet size
• OASIS standard protocol

Pros

• Flexibility to choose the quality of services with the given functionality
• Lightweight
• Standardized by OASIS Technical Committee
• Easy to implement

Cons

• High power consumption because of TCP-based connection
• Lack of encryption

Use

A parking lot with several parking sensors installed to find the number and location of vacant parking spots.

AMQP (Advanced Message Queue Protocol)

AMQP is an open standard application layer protocol used for sending transactional messages between servers. This binary protocol was designed to support messaging applications and communication patterns. It can process thousands of reliable transactions due to message-centric middleware. This messaging protocol for IoT makes sure that messages are not lost while transferring using TCP or UDP. However, it is not exclusively built for the Internet of Things but is still compatible with message communications with IoT scenarios. Its origin was in the banking industry with the intention to track messages and ensure that they are delivered as intended without any failures or reboots.

Features

• Binary application layer
• Compatible with messaging scenarios
• Also used for point-to-point and publish-subscribe messaging
• Supports end-to-end encrypted messages

Pros

• Messages can be easily sent over TCP and UDP
• End-to-end encryption

Cons

High resource utilization, i.e. power and memory usage

Use

AMQP is common in business messaging where it is used to define devices like mobile handsets, communicating with back-office data centers.

XMPP (Extensible Messaging and Presence Protocol)

XMPP was originally known as Jabber and was developed for real-time messaging, contact list maintenance, and presence information. This messaging protocol is based on Extensible Markup Language (XML) and is more recently used for publish-subscribe messaging, IoT, VoIP (Voice over IP), gaming, and other systems. The primary feature of this communication protocol is its addressing mechanism that enables two devices or nodes to exchange information or data regardless of how far the devices are in the network. It identifies the nodes in the network using Jabber ID (JID) that follows a standard address. XMPP uses a polling mechanism to locate the destination of the messages which are transmitted over TCM connection. It is implemented using a client-server architecture where the client starts an XML stream as he sends an open tag, and the server reverts with the XML stream. As it is an open IoT protocol, anyone can have an XMPP server without connecting to the internet.

Features

• Designed to be extensible
• Open standard
• Client-server architecture

Pros

• Addressing scheme to identify devices on the network
• Client-server architecture

Cons

• Text-based messaging, hence no end-to-end encryption
• No quality of service provision

Use

A smart thermostat with smartphone accessibility and a gaming console with instant messaging feature between the online players.

DDS (Data Distributed Service)

DDS is also based on the publish-subscribe model and is designed to be used with real-time systems. It is an Object Management Group machine-to-machine standard and connects the devices directly unlike MTTQ that connects devices to servers, thereby making DDS a faster protocol.  As it eliminates any communication with the server, this application protocol for IoT is known to deliver millions of messages to numerous receivers within no time. It can be used to address the unique needs of mobile applications, including defense, medical devices, robotics, aerospace, air-traffic control, power generation, autonomous vehicles, transportation system, and other real-time information exchange systems. The main goal is to enable dependable, scalable, high-performance, interoperable data exchange.

Features

• Designed for real-time systems
• Based on the publish-subscribe model
• Connects devices directly to each other
• Low overhead

Pros

• Flexible and adaptable architecture
• Low overhead and can be used with high-performance systems
• Deterministic data delivery
• Scalable
• Efficient use of transport bandwidth

Use

Medical imaging, military systems, automotive testing,  wind farms, asset-tracking systems.

CoAP (Constrained Application Protocol)

CoAP is a specialized IoT Message Application Protocol with a client-server architecture. As the name suggests, it is designed for resource-constrained devices so that clients and servers can exchange data through connectionless datagrams. It requires low power, can work across lossy networks, and can connect devices to each other or to other nodes on the internet. CoAP is a document transfer protocol that runs on User Datagram Protocol (UDP). Apart from IoT scenarios, it can also be used for SMS on mobile communication networks.

Features

• Uses low power
• Designed for constrained devices

Pros

• Uses DTLS for security
• Faster device-to-device communication
• Smaller packet size
• Well-designed protocol

Cons

• Doesn’t offer broadcast message facility as it is a one-to-one protocol
• Reliability is the application’s responsibility

Use

Smart energy grids and smart homes.

Wrapping It Up!

The protocols mentioned above are applicable to different operating scenarios and depending on the IoT devices that you want to integrate into your solution, you can select the required one. Yes, you can also pick one specific IoT communication protocol as a standard solution but make sure that you consider all the pros and cons before making the decision. Go through its features, such as security, service, reliability. Connect with a trusted IoT solution provider, A3logics, for the right implementation and solution. Rest assured that with us you will attain your objectives efficiently and effectively.

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