Instead of directly delivering each event to the configured destination services and waiting for each service to acknowledge the event, Digital Event Services (DES) stores the event in an internal queue.

Depending on the delivery mode setting defined for each event type in Command Central, the queue can be held in-memory or on-disk. After an event is added to the queue, DES is ready to accept new events. In the meantime, the queued events are delivered to their destination services by a separate thread in the order in which they were added to the queue.

For more information about how to configure delivery mode per event type, see Configuring Event Type Associations.