Inventory service maintains the IPv4 prefix list and route map information in its DB. As part of device update, diff is computed for these entities, and if there is a diff, an event is published.
Policy service subscribes to the events from inventory service-related IP prefix list
and route map and updates the app state of these entities. The entities for which
the app state is in
reconciled as part of DRC.
To handle attribute level drift, DB maintains a bitmap to show exactly which attribute has drifted as part of DRC show output.
Policy service publishes events when you create, update or delete prefix lists and route maps.