A Comprehensive Guide to Understand the Role of MQTT Protocol in IoT Messaging

A Comprehensive Guide to Understand the Role of MQTT Protocol in IoT Messaging

Role of MQTT Protocol in IoT Messaging

Are you interested in setting up a budget-friendly, scalable IoT network for the thousands of devices you use in your business?

Then you should definitely consider the MQTT protocol in IoT.

What is MQTT Protocol in IoT?

Before we delve into what is MQTT in IoT is, we need to look at the history of MQTT itself. In 1999, IBM employees invented Message Queuing Telemetry Transport (MQTT) as a messaging protocol. In its initial version, MQTT helped oil pipeline sensors communicate with satellites.

In the following two decades since its inception, MQTT became the go-to messaging protocol used by IoT devices.

In 2014, Oasis accepted MQTT as an ISO standard, thus marking its universal rise as an IoT messaging protocol.

Today, MQTT in IoT helps to connect millions of devices across numerous industries.

How Does MQTT Work – The Publish/Subscribe Architecture

Let us now understand in detail how the MQTT protocol architecture in IoT or the Pub/Sub model is set up. As we know, any IoT network consists of thousands or millions of tiny devices called sensors. In MQTT parlance, these MQTT IoT devices are known as ‘clients.’

The clients can be of two types, depending on whether they are transmitting information or receiving information. Clients who transmit information to other devices are called ‘publishers.’ Clients who receive information transmitted by publishers are called ‘subscribers.’

Subscriber client devices can subscribe to any topic of information or even sub-topics. In complex networks, hierarchy structures are present for various topics and sub-topics.

In MQTT, servers called IoT MQTT brokers to transmit information between clients. In practical terms, MQTT brokers are cloud-based servers from platforms such as Amazon Web Services, Microsoft Azure, or Google Cloud. These brokers transmit information seamlessly between publishers and subscribers, thus transmitting information in the entire IoT network.

How Does MQTT work—Message Structure and QoS Levels

MQTT protocols also use a concept called Quality of Service or QoS levels to ensure transmission of messages even during unstable connections between devices. In the MQTT protocol, there are three QoS levels:

  1. QoS 0: Also called “at most once,” in this level, the message is sent at most once, without any guarantee of delivery. This level is used when connections between devices are stable and the message is not critical.
  2. QoS 1: Also called “at least once,” in this level, the message is sent repeatedly until the delivery is confirmed by the receiver. This level is used to transmit critical messages whose delivery needs to be guaranteed.
  3. QoS 2: Also called “exactly once,” in this level, the message is sent only once. Guaranteed delivery requires technical coordination between sender and receiver, and thus this level is more energy-consuming than the other two levels.

Advantages of MQTT

MQTT protocol is essentially a lightweight IoT protocol with several advantages:

  1. Lightweight and efficient: MQTT protocol requires a minimal amount of code and consumes very less power. The MQTT protocol is thus energy-efficient and easy to deploy for millions of devices.
  2. Connecting devices during unreliable networks: MQTT in IoT uses QoS levels to ensure guaranteed delivery of messages to receivers, even when connections between devices are unreliable.
  3. Enabling communication between the cloud and devices: MQTT protocol for IoT ensures speedy communication between cloud servers and IoT devices in remote areas.
  4. Last will feature: If any IoT device disconnects unexpectedly, MQTT protocol uses the last will feature to broadcast a relevant message to other IoT devices in the network.
  5. Extensive programming support: MQTT has extensive support in programming languages such as Python, making it very easy for developers to use it.

How is MQTT Used in IoT?

Let us now look at MQTT IoT examples.

  1. Automotive: MQTT IoT projects in the automotive sector enable vehicle theft prevention, vehicle monitoring, and remote maintenance of vehicles.
  2. Logistics: One of the best MQTT protocols in the IoT example is in the logistics sector. MQTT IoT hubs such as Airtel IoT help track freight vehicles and provide real-time alerts for freight safety and movement.
  3. Energy: IoT MQTT panels in the energy sector help to build a smarter energy grid and optimise power consumption by consumers.
  4. Home automation: IoT dashboards use MQTT to manage home devices instantly with your mobile phones.

MQTT alternatives

MQTT is one of several IoT messaging protocols. Let us now see how MQTT stacks up against the other messaging protocols in IoT.


XMPP protocol uses XMP language and is more code-heavy and bandwidth-consuming than MQTT. It also does not use the pub/sub model by default. MQTT is therefore far superior to use than XMPP.


HTTP(S) is the language of the web and thus enables communication with web applications. However, it is heavier in code use than MQTT and thus needs more power. Moreover, HTTP(S) cannot transmit many messages simultaneously, thus reducing the effectiveness of network communication.


AMQP is also a lightweight protocol. However, compared to MQTT, it is a more complex messaging system and thus uses more power and memory than MQTT.

Thus, MQTT is a clear favourite when it comes to IoT communication.

How to make MQTT secure?

The MQTT protocol has its vulnerabilities. It uses TLS/SSL cryptographic protocols and has a weak authentication mechanism. However, advanced IoT solutions providers such as Airtel IoT use telco-grade security with a dedicated private network to ensure all transmission of data in your IoT network is secure.

Deploy MQTT in your IoT network

MQTT is hands down the best messaging technology to deploy for your IoT network. It is low cost, fast, lightweight, and scalable. It has its security issues, but a tie-up with a reliable cellular partner can ensure your IoT network uses MQTT securely and without any hassle.

Airtel Business

Airtel Business is India’s leading and most trusted provider of ICT services with a global network across the USA, Europe, Africa, Middle East, Asia-Pacific, India and SAARC regions. We serve over 1200 global enterprises, 2000 large and 1 million medium/small businesses across India.