--- title: Command dispatch description: How an operator command reaches a possibly-offline device and is confirmed. --- # Command dispatch Commands flow the opposite direction to telemetry: from a human (or an automation) down to a specific device. Because devices are intermittently connected, dispatch is **store-and-forward** with priority and delivery guarantees rather than fire-and-forget. A command may be issued while the target device is asleep or offline. The [**Priority Queue**](:obj:@example-iot.product.ingestion.command_router.priority_queue) holds it until the device reconnects, ordered so safety-critical commands jump ahead of routine ones. ## Participants Validates, persists and routes outbound commands. Delivers the command to the device's session. Applies the command and reports the result. ## Steps ### Issue An operator issues a command from the dashboard; the [**Command Router**](:obj:@example-iot.product.ingestion.command_router) validates it and writes it to the command repository. ### Queue by priority The command is enqueued; safety-critical commands are dispatched ahead of routine configuration changes. ### Deliver on connect When the device has an active session the broker delivers the command to the edge agent. ### Acknowledge The device actuates and the result flows back as a delivery receipt, surfaced to the operator as `applied` (or `failed`).

Number	Source	Destination	Description
1	Operator	Dashboard	Issue command
2	Dashboard	Command router	POST command
3	Command router	Priority queue	Enqueue (priority)
4	Priority queue	MQTT broker	Dispatch when device online
5	MQTT broker	Edge agent	Deliver command
6	Edge agent	Device	Actuate
7	Device	Edge agent	Result
8	Edge agent	MQTT broker	Ack
9	MQTT broker	Command router	Delivery receipt
10	Command router	Dashboard	Status: applied