MQTT is the most commonly used protocol for small sensors and mobile devices in small and large scale IOT Deployments. It is a lightweight messaging protocol that uses publish/subscribe operations to transfer data between clients and the server. This protocol runs over TCP/IP. It also provides ordered, bandwidth-efficient, lossless and bi-directional support. MQTT protocol provides secured data transfer, helps in building inter-operable brokers across different vendors, Manages re-transmission of messages and guarantee delivery, notify about the disconnected client, provides instant event notifications for distributed applications.