Plain MQTT says nothing about what topics mean or how payloads are formatted, so every integrator invents a scheme. Sparkplug fixes a topic namespace of group, edge node and device, a Protocol Buffers payload with typed metrics and timestamps, and a set of birth and death certificates that let a consumer know which devices are online and what metrics they publish.
The point is plug-and-play interoperability: a SCADA system, a historian and an analytics tool can all subscribe to the same broker and understand every edge node without custom parsing. Report-by-exception keeps bandwidth low, and a primary application can flag when it goes offline so edge nodes buffer data. The trade-off is reduced flexibility, and the state model assumes a single primary host, which can complicate multi-consumer architectures. MQTT explained covers the underlying protocol.
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