The MQTT (Message Queue Telemetry Transport) library provides a lightweight publish/subscribe (or PubSub) messaging protocol that runs on top of TCP/IP and is often used in Machine to Machine (M2M) and Internet of Things (IoT) use cases. The MQTT library implements a subset of the MQTT 3.1.1 protocol standard.
An MQTT connection to a broker can be established in a non-secure and secure manner. Especially in IoT use cases, TLS (Transport Layer Security) is used to provide a secure communication protocol between a client and sever. In TLS, the client and server establish a secure connection through a handshake protocol to prevent eavesdropping from any malicious parties.
The FreeRTOS+ libraries can be used individually or collectively to create locally connected or internet connected MCU applications. Each library can be freely used and is distributed under the MIT open source license.