In the Cisco DNA Center Intent API, when creating an event subscription via a POST to
/dna/intent/api/v1/event/subscription, the correct key to specify the list of endpoints that should receive event notifications is "subscriptionEndpoints". This field must contain endpoint definitions including URL, method, and connector type.

Asynchronous APIs allow the client to send a request and continue processing without waiting for the response. This improves application scalability by freeing up resources to handle other tasks while waiting for the operation to complete.

Explanation:
On-change subscriptions are event-driven and ideal for conditions like traffic spikes or OSPF neighbor loss that occur unpredictably and require immediate attention.
Periodic subscriptions are time-based and suited for regularly collected metrics like CPU and memory usage, where consistent monitoring is more important than instant reaction.

The YANG module tree in the first image shows a module named interfaces with a container interfaces, a list interface keyed by name, and four leaves: name, address, subnet-mask (all strings and mandatory), and enabled (boolean, optional).