Tutorial: MQTT

MQTT stands for MQ Telemetry Transport. It is essentially a simple format for sending small data packages back and forth. It is a publish/subscribe, extremely simple and lightweight messaging protocol that is optimized to connect physical world devices and events with enterprise servers and other consumers. It is designed for constrained devices and low-bandwidth, high-latency or unreliable networks. The design principles are to minimise network bandwidth and device resource requirements whilst also attempting to ensure reliability and some degree of assurance of delivery.

These principles also turn out to make the protocol ideal of the emerging “machine-to-machine” (M2M) or “Internet of Things” world of connected devices, and for mobile applications where bandwidth and battery power are at a premium. It is described as a machine-to-machine(M2M)/IoT connectivity protocol and is so lightweight that it can be supported by some of the smallest measuring and monitoring devices. It can transmit data over far reaching, sometimes intermittent networks.

MQTT is designed to overcome the challenges of connecting the rapidly expanding physical world of sensors, actuators, phones, and tablets with established software processing technologies. TCP/IP port 1883 is reserved with IANA for use with MQTT. TCP/IP port 8883 is also registered, for using MQTT over SSL.

Refrences:

• http://www.rs-online.com/designspark/electronics/blog/building-distributed-node-red-applications-with-mqtt
• http://pubsubclient.knolleary.net/
• https://github.com/knolleary/pubsubclient
• http://www.rs-online.com/designspark/electronics/blog/an-mqtt-powered-display-using-an-arduino-ethernet-and-lcd
• https://github.com/francoisvdm/TT3
• https://github.com/mqtt/mqtt.github.io/wiki/software?id=software
• http://stackoverflow.com/questions/32327512/mqtt-between-arduino-and-raspberry-pi
• http://forum.arduino.cc/index.php?topic=330222.0
• http://tech.scargill.net/mqtt-on-arduino/
• http://jpmens.net/2013/02/25/lots-of-messages-mqtt-pub-sub-and-the-mosquitto-broker/
• https://www.element14.com/community/groups/arduino/blog/2015/03/14/getting-data-over-the-internet-with-arduino