Difference in API and User Level Advance Resource throttling in WSO2 API Manager 2.0

From WSO2 API Manager 2.0 throttling implementation onward 2 different throttling levels have been introduced in Resource Level throttling.

When you login to admin dashboard you can see Advance resource throttling tier configurations under throttle policies section as given in the below screenshot.

When you add a resource tier, you can select either API or resource level as below.

API Level Resource Tier

For API level policy, it is the shared quota of all applications that invoke the API.
if someone selects API Level policy then selecting resource level policy will be disabled.

So as an example if there are 2 users subscribe to the same api, the request count or bandwidth  defined to the API is applicable for both users as a shared quota. So if you have defined 10000 requests per minute both users can share that amount.

User Level Resource Tier

For User level policy, it is the quota assigned to each application that will invoke the API.
So the quota is assigned for single user who can access the particular API from multiple applications. Simply when it's user level, throttle key will be associate with user name.

So as an example if you have selected user level, and when there are 2 users subscribed to the same API, the defined count in tier will be assigned to each user. So if you have defined 10000 requests per minute, both users get 10000 requests /1 minute per each as a total of 20000 requests.