MQTT protocol is a lightweight, open and simple network protocol for the device communications. It is based on the principle of publishing messages and subscribing to topics, or "pub/sub". The protocol runs over TCP/IP, or over other network protocols that provide ordered, lossless, bi-directional connections. It was designed for the low-bandwidth, high latency networks in the late 1990s/early 2000s and its support to connect over thousands of clients to a single server. This characteristic is a suite for the devices which has very limited processing powers and limited memory, such as sensors, mobile devices, monitoring devices. Since It provides a common interface for everything, new sensors or devices can integrate very easily with the system. Message in MQTT is published on topics. These topics are treated as a hierarchy separate using slash(/) as a separator like in the file system. Clients can receive messages ...