ST STM32L4 Manual page 96

•
MQTT uses a client/server model where every IoT device is a client and
is connected to a server, called an MQTT broker (example: Azure IoT
Hub).
•
The clients send messages to an address, called a topic. The MQTT
broker will forward that message to all the clients subscribed to that
topic.
Subscribed to "LED" topic
"On"
Thing_y
How MQTT Works
Thing_x
Publish "On" to the "LED" Topic
LED
"On"
MQTT Broker
Thing_z
Subscribed to "LED" topic
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