AAA refers to a framework for intelligently controlling access to computer resources, enforcing policies, auditing usage, and providing the information required to bill for services.

So, here in AAA, we know that every single "A" has its own meaning. Let's take a deep dive into the concept.

Authentication

Authentication refers to authentication, or we can say the verification of the user by having a valid username and password before getting access to any particular service or device.

Authorization

Once the user is authenticated, that user may be authorized for different types of access or activity. Authorization is a process via which we enforce policies for specific users according to the need.

Like here we have -

• Privileges and restrictions (for specific users)

Accounting

Accounting is defined as keeping track of things done inside the network as the name represents that to keep a log of tracks which can include the total amount of consumed time and data. This information of logs and tracks can be used for audit and reporting.

For example, with accounting, you could get logs and every update when the user logged in and when the user logged out.

Learn here - What is AAA