The Authentication, Authorization, and Accounting (AAA) protocol provides the necessary framework to enable scalable access security.
The framework is designed to control who is allowed to connect/access network resources, what they are allowed to do when they are connected, and keeps track of who logged in and what they did while logged in. The AAA framework is the logic behind the identity management system.
Authentication
Users/admins must prove that they are whom they say they are.
Using either username and password combinations, challenge and response questions, token cards, or other methods.
Authorization
After being authenticated, authorization determines which resources they can access and which operations they are allowed to perform.
Accounting
Accounting also known as auditing, records what the user does, including what is accessed, the amount of time the resource is accessed, and any changes that were made. Accounting keeps track of how network resources are used.
This concept of AAA can be explained using the use of a credit card, as shown in the figure. The credit card identifies who can use it, how much that user can spend, and keeps account of what items the user spent money on.
The AAA framework is a key feature of maintaining security and protection of the user, allowing and giving access to the necessary information to the user, and keeping an eye on what the user is accessing.