July 2017
Beginner to intermediate
378 pages
10h 26m
English
Content preview from Analytics for the Internet of Things (IoT)
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Last Will and Testament (LWT)
This creatively named feature helps MQTT deal with lossy networks and enhances scalability. It is a message that can be stored on the broker in case the publisher drops off the network unexpectedly.
It stores state and purpose including the commands it published and its subscriptions. When it drops out, the broker notifies all subscribers of the LWT. When it returns, the broker sends it back to its prior state.