Demo of an MQTT application that establishes a plaintext (no encryption) TCP connection with the server, and uses QoS 0 level of communication with broker.

This demo uses a POSIX socket-based transport interface implementation to establish a TCP connection, and demonstrates the subscribe-publish workflow of MQTT at Qos 0 level. After subscribing to a single topic filter, it publishes to the same topic and waits for receipt of that message to be returned from the server at QoS 0 level. This cycle of publishing to the broker and receiving the same message back from the broker is repeated indefinitely.

Messages in this demo are sent at QoS 0, which guarantees at most one delivery according to the MQTT spec. See the demo workflow below: