IoT – The Protocols Used In The IoT World

The world of IoT – or the Internet of Things – is revolutionizing how we interact with devices daily, especially when we realize the ability to connect to the world wide web.

This wide connection also allows the exchange of information constantly and in real-time. The protocols used for this communication are equally crucial for the success of the development of the technology.

MQTT and REST are the two protocols that stand out and dominate the scene in the Internet of Things world, both with positives and negatives, and several applications used in connected devices. From the principles and rules of REST to the ease and lightness of MQTT, both communication protocols make the ideal solution for the IoT world.

And you want to know more about MQTT and REST and their importance in the world of IoT? Keep following our publication!

The IoT World And Communication Protocols

The Internet of things is revolutionizing the world of technology and how users interact with their devices, bringing information and directly impacting digital transformation. Several cloud platforms, sensors, equipment, and modules have been launched by manufacturers focused on developing IoT solutions.

The desire to connect the most varied objects, electronic devices and electronic and computational systems for exchanging information and data is part of the aspirations of digital transformation, especially when addressing the evolution of Industry 4.0 concepts. Also called the Fourth Industrial Revolution has developed the industrial environment favoring automation, artificial intelligence, modularization, and other pillars linked to innovation and technology.

IoT and Industry 4.0 go hand in hand in the evolution of computing and these new technologies, especially when considering embedded systems and the development of protocols. The implementations of these communication protocols evolved from industrial protocols, such as Modbus and Fieldbus, to more comprehensive and efficient ones, such as MQTT and REST.

Both protocols are also widely used in the software development world and new architectures such as microservices. The ease of integration, lightness in transmitting information, and breadth in applying these protocols promote this type of use.

MQTT and REST have benefits and positive characteristics inherent to their development, and both are used in the IoT world.

The MQTT Protocol

The MQTT ( Message Queue Telemetry Transport ) protocol is an IoT Machine-to-Machine (M2M) communication protocol. Its description also highlights its characteristic of extreme lightness in the message transport project through the publication and subscription of topics. It is beneficial in communication systems with bandwidth restrictions and high latency in data transmission.

IBM created it in the 1990s to be used in supervisory and data acquisition systems in an industrial setting, the SCADA ( Supervisory Control and  Data Acquisition). From the success of this type of application, it was also migrated to the IoT world.

MQTT And The Publish And Subscribe Model

The basic concept of the MQTT protocol is its publish and subscribe (or publish/subscribe ) model, which consists of two basic types of entities: a message broker and clients. The broker is a large server that receives all messages from its clients and sends them to the destination clients – and as an example, some clients can be anything from IoT sensors or even an application that receives data from sensors and processes them.

  • The subscription arises because the client connects and “subscribes” to some specific topic of messages in the broker;
  • The other client then publishes messages on that topic, sending the message and subject to the broker;
  • This broker then makes this message available in the topic, and the first client that performed the subscription receives the message.

An excellent example of a subscribed topic is: ‘area/Area Identification/Sensor/Sensor Identification/temperature.’ All information is separated by slashes “/,” and these topics can be created according to business rules. A sensor subscribed to this topic will send temperature reading messages. In contrast, the application subscribed to the same topic receives this data, processes it, and may send the data processed through another case to another application.

Protocol Security And Quality

The MQTT protocol has several message settings ranging from encryption to quality of service (also known as QoS, Quality of Service ). QoS ranges from 0 to 2:

  • QoS 0, there is no message delivery confirmation, and the sender does not store the message for retransmissions;
  • QoS 1, which has delivery confirmation with acknowledgment performed;
  • QoS 2 guarantees the delivery of the message exactly once, with the sending of a declaration of receipt.

The REST Protocol

The REST protocol (or  Representational State Transfer which in Portuguese is Representational State Transfer) is an abstraction of the WEB architecture with its principles, rules, and limitations to allow the creation of the project with the data transmission interfaces of a well-defined way, with the most critical operations like POST, GET, PUT and DELETE.

Web Services allow a comprehensive interaction between systems connected over the Internet and are a great way to connect applications with fast performance, reliability, and the ability to scale the service. Requests for this application get a response in XML, HTML, and even JSON format, depending on what is being analyzed.

The emergence of REST occurred in 2000 by Roy Fielding in his master’s thesis, which described the design of software architecture built for network applications. In this way, network communication also benefits IoT applications by creating applications that can receive and process data and return it to other systems.


REST allows the existence of resources that are used through a global identifier and that manipulate these resources through the components of the network – or the clients and servers. Communication through the HTTP interface makes exchanging information through joint operations in this type of connection possible.

The connection of equipment in the IoT world through the REST protocol is facilitated through the use of the HTTP interface. It allows the use of the Internet to carry out this communication. Smart devices can connect to the Internet and are also usable by other devices, allowing an exchange of information in fact and intelligent analysis of data through different connected systems.

Also Read: IoT – Internet Of Things, Security Concepts And Challenges

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