What is MQTT?
MQTT (MQ Telemetry Transport or Message Queuing Telemetry Transport) is a ISO standard (ISO/IEC PRF 20922) publish-subscribe-based messaging protocol. It works on top of the TCP/IP protocol. It is designed for connections with remote locations where a "small code footprint" is required or the network bandwidth is limited. It is useful when combined with networked power switches in order to remotely control the power switch by sending commands to the switch in the form of messages on the message queue.