{"id":309,"date":"2017-05-24T07:24:01","date_gmt":"2017-05-24T14:24:01","guid":{"rendered":"http:\/\/www.kenwalger.com\/blog\/?p=309"},"modified":"2017-05-24T08:35:50","modified_gmt":"2017-05-24T15:35:50","slug":"overview-mqtt","status":"publish","type":"post","link":"https:\/\/www.kenwalger.com\/blog\/iot\/overview-mqtt\/","title":{"rendered":"Overview of the MQTT Protocol"},"content":{"rendered":"

There are several different ways one can utilize to connect an Internet of Things (IoT) device to a network. I have previously<\/a> discussed some of the setup for a NodeMCU development board<\/a>\"\" to connect to a WiFi network. In an IoT environment full blown network protocols such as HTTP can be a bit heavy. A popular, lighter weight, solution I’d like to discuss the basics of is\u00a0MQTT.<\/p>\n

MQTT<\/h3>\n

While MQTT\u00a0used<\/em> to stand for MQ Telemetry Transport, it\u00a0is now classified as\u00a0not<\/strong> being an acronym. So what is it? What does it do? Well, it is a messaging protocol using TCP<\/a> of TCP\/IP fame to provide publish\/subscribe services. It was, and is, designed for small, constrained devices and makes design decisions based on those constraints. Concepts which are important in the IoT world, such as memory, bandwidth, latency, power consumption, and network reliability. Let’s focus in on one of the main MQTT concepts, the publish\/subscribe pattern.<\/p>\n

MQTT Publish\/Subscribe Pattern<\/h3>\n

In a publish\/subscribe pattern a client publishes information and another client can\u00a0subscribe<\/em> to the information it wants. In many cases there is a broker between the clients who facilitates and\/or filters the information. This allows for a loose coupling between entities.<\/p>\n

The decoupling can occur in a few different ways, space, time, and synchronization.<\/p>\n