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 cfg-refreshed or cfg-entry-deleted, is
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.