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Imagine that we have dozens of different devices that must exchange data between themselves. These devices have to request data from other devices, and the devices that receive the requests must respond with that data. The devices that request the data must process the data received from the devices that responded with the required data.

The devices are Internet of Things (IoT) boards that have dozens of sensors wired to them. We have the following IoT boards with different processing powers:

Raspberry Pi 3 Model B+
Qualcomm DragonBoard 410c
Udoo Neo
BeagleBone Black
Phytec phyBoard-i.MX7-Zeta
e-con Systems eSOMiMX6-micro
MinnowBoard Turbot Quad-Core

Each of these boards has to be able to send and receive data. In addition, we want a web application to be able to send and receive data. We want to send and receive data in near-real time over the internet, and we might face some network problems: our wireless networks are somewhat unreliable and we have some high-latency environments. Some devices have low power, many of them are powered by batteries, and their resources are scarce. In addition, we must be careful with the network bandwidth usage because some of the devices use metered connections.

A metered connection is a network connection where we have a limited amount of data usage per month. If we go over this amount of data, we get billed extra.

We can use HTTP requests and build a publish-subscribe model to exchange data between different devices. However, there is a protocol that has been specifically designed to be lighter than the HTTP 1.1 and HTTP/2 protocols. The MQ Telemetry Transport (MQTT) is better suited for a scenario in which many devices have to exchange data between themselves in near-real time over the internet and we need to consume the least network bandwidth possible. This protocol works better than HTTP 1.1 and HTTP/2 when unreliable networks are involved and connectivity is intermittent.

The MQTT protocol is a machine-to-machine (M2M) and IoT connectivity protocol. MQTT is a lightweight messaging protocol that works with a server-based publish-subscribe mechanism and runs on top of TCP/IP (Transmission Control Protocol/Internet Protocol). The following diagram shows the MQTT protocol on top of the TCP/IP stack:

The most popular versions of MQTT are 3.1.1 and 3.1. In this book, we will work with MQTT 3.1.1. Whenever we reference MQTT, we are talking about MQTT 3.1.1, the newest version of the protocol. The MQTT 3.1.1 specification has been standardized by the OASIS consortium. In addition, MQTT 3.1.1 became an ISO standard (ISO/IEC 20922) in 2016.

MQTT is lighter than the HTTP 1.1 and HTTP/2 protocols, and therefore it is a very interesting option whenever we have to send and receive data in near-real time with a publish-subscribe model, while requiring the lowest possible footprint. MQTT is very popular in IoT, M2M, and embedded projects, but it is also gaining presence in web applications and mobile apps that require assured messaging and an efficient message distribution. As a summary, MQTT is suitable for the following application domains in which data exchange is required:

Asset tracking and management
Automotive telematics
Chemical detection
Environment and traffic monitoring
Field force automation
Fire and gas testing
Home automation
In-Vehicle Infotainment (IVI)
Medical
Messaging
Point of Sale (POS) kiosks
Railway
Radio-Frequency Identification (RFID)
Supervisory Control and Data Acquisition (SCADA)
Slot machines

As a summary, MQTT was designed to be suitable to support the following typical challenges in IoT, M2M, embedded, and mobile applications:

Be lightweight to make it possible to transmit high volumes of data without huge overheads
Distribute minimal packets of data in huge volumes
Support an event-oriented paradigm with the asynchronous, bidirectional, low-latency push delivery of messages
Easily emit data from one client to many clients
Make it possible to listen for events whenever they happen (event-oriented architecture)
Support always-connected and sometimes-connected models
Publish information over unreliable networks and provide reliable deliveries over fragile connections
Work very well with battery-powered devices or require low power consumption
Provide responsiveness to make it possible to achieve near-real-time delivery of information
Offer security and privacy for all the data
Be able to provide the necessary scalability to distribute data to hundreds of thousands of clients

Key benefits

<ul><li>Make your connected devices less prone to attackers by understanding security mechanisms</li>

<li>Take advantage of MQTT features for IoT and Machine-to-Machine communications</li>

<li>The only book that covers MQTT with a single language, Python</li>

</ul>

Description

MQTT is a lightweight messaging protocol for small sensors and mobile devices. This book explores the features of the latest versions of MQTT for IoT and M2M communications, how to use them with Python 3, and allow you to interact with sensors and actuators using Python. The book begins with the specific vocabulary of MQTT and its working modes, followed by installing a Mosquitto MQTT broker. You will use different utilities and diagrams to understand the most important concepts related to MQTT. You will learn to make all the necessary configuration to work with digital certificates for encrypting all data sent between the MQTT clients and the server. You will also work with the different Quality of Service levels and later analyze and compare their overheads. You will write Python 3.x code to control a vehicle with MQTT messages delivered through encrypted connections (TLS 1.2), and learn how leverage your knowledge of the MQTT protocol to build a solution based on requirements. Towards the end, you will write Python code to use the PubNub cloud-based real-time MQTT provider to monitor a surfing competition. In the end, you will have a solution that was built from scratch by analyzing the requirements and then write Python code that will run on water-proof IoT boards connected to multiple sensors in surfboards.

What you will learn

<ul><li>Learn how MQTT and its lightweight messaging system work</li>

<li>Understand the MQTT puzzle: clients, servers (formerly known as brokers), and connections</li>

<li>Explore the features included in the latest versions of MQTT for IoT and M2M communications</li>

<li>Publish and receive MQTT messages with Python</li>

<li>Learn the difference between blocking and threaded network loops</li>

<li>Take advantage of the last will and testament feature</li>

<li>Work with cloud-based MQTT interfaces in Python</li>

</ul>

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Frequently bought together

€29.99

MQTT Essentials - A Lightweight IoT Protocol

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Total € 95.97

LAURENT Feb 12, 2019

Really good book ! Easy to understand (clear examples and no errors as far as i can see)Will definitely buy another version if author can make a longer chapter on multithreading (a bit short in this book) and an introduction to another mqtt server (as vernemq for example) for shared subscriptions and clustering (not present on mosquitto).

Amazon Verified review

Kurt Keller Jul 18, 2019

There are good things about this book and not so good things. At around 200 pages, the book is not too big. It is easy to read, kept in understandable language. But at this page count, it feels overly repetitive: "We are going to see how to do X", "To do X do X.1", "To do X do X.2", "To do X, do X.3", "We have seen how to do X".The story used in the book to go along is about monitoring and/or controlling drones, small vehicles or surfboards. But it does not require you to actually own one of the boards or devices mentioned, everything is kept in 'simulation mode' and can be run on a PC.What I definitely like about the book is, that it shows you how to perform everything you need to follow along. The author does not assume that you know how to install a Mosquitto server or how to setup a venv environment in Python, or how to create self signed SSL certificates. He explains all these steps detailed in an easy to follow way for those readers who may not be familiar with these tasks. So to follow along, you don't really need to know much, you'll really be guided well through everything required. Before the book starts with the actual programming (after more than half the page count), it does explain MQTT and shows how it works and how to use it. So it is, in my opinion, mostly a book about MQTT and explains how this protocol works and how to use it with Python code. If your main goal is to learn about MQTT, a good choice.If you are more interested in how to write Python code interacting with MQTT, rather than how MQTT works, then I would not really recommend this book. I am not a professional programmer, but neither is Python something new for me. Although the code presented and built step by step does work, it is, in my opinion, quite flawed. Connections to the MQTT server are stored as class variables, rather than instance variables (which I still could see as useful in certain specific situations); class methods are declared as static methods (normally used if the method does not need anything from the class) but then access things in the class by referencing the class name; a method is created which builds a non-changing dictionary from scratch each time the method is called... Again, I am not a professional programmer, but to me the code looks like a mess. Personally, I only used a few lines from it, had a look at the paho.mqtt.client help and successfully and quickly built my project in a way I think is more sensible.You want an introduction to MQTT and/or the Mosquitto Server? This book is OK for you. You want to learn how to write Python code accessing an MQTT server? Don't use this book.

Ben de Leur Jun 21, 2019

The table of contents states that a class will be made to control a motor via mqttThis was the reason for me to buy this bookIt appears to be a dummy class with only stubs ...Total scams

Hands-On MQTT Programming with Python: Work with the lightweight IoT protocol in Python

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