Flow Controllers and Priority on Order Queues

The flow controller is responsible for deciding from which order queue to dequeue a message:

  • An order queue signals the flow controller that it has a message waiting to continue downstream in the Fulfillment Provisioning flow.

  • When the flow controller has a request level lower than the configured high water mark, it triggers the order queue to inject a message into the flow.

There may be multiple order queues with pending service orders waiting for injection and the flow controller provides a way to decide which queue will be flushed first.