Understanding MQTT QOS Levels- Part 1

MQTT provides 3 QOS levels- QOS 0 – Once (not guaranteed) QOS 1 – At Least Once (guaranteed) QOS 2 – Only Once (guaranteed) The QOS levels are a way of guaranteeing message delivery and they  refer to the connection between a broker and a client. In this two part tutorial we will look in detail at the message flow when publishing using all three QOS levels. We also look at the advantages and disadvantages of using the various levels

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