The scaling up and down or scaling in and out operations are required to effectively utilize underlying resources based on the requirements. For example, for an online shopping website, we can predict that it will have a huge number of requests during festival days. It may have a moderate number of requests on normal weekdays. In such a scenario, it is better to keep more resources available to manage user requests and decrease the number of resources on normal days. If we can automate this scale in and scale out operation, then it is the best utilization of resources and customers also won't face any issues.
Both the operations are performed on the ASP.