In an Internet of Things (IoT) solution, IoT devices send events (notifications, acknowledgments, telemetry) to application to gain insights. Applications may require specific subsets of events for processing or storage at different end points. These events may also need to be routed to different services for further processing. As the IoT solution scales out, the number of devices, volume of events, variety of events and different services also varies. A flexible, scalable, consistent, and reliable method to route events is necessary to serve this pattern.

https://learn.microsoft.com/en-us/azure/architecture/example-scenario/iot/event-routing