The AAA framework consists of three distinct security components:

1. Authentication is the process of verifying a user's identity to ensure they are who they claim to be. The statement "It verifies 'who you are'" is the fundamental definition of this phase. Technical validation of these credentials often occurs via protocols like TACACS+ or RADIUS.
2. Accounting measures and records the resources a user consumes during their session. This includes logging session statistics such as the duration of each connection and collecting data to support User Access Reporting for auditing, billing, or security review.

Cisco Systems. Authentication, Authorization, and Accounting Overview. Cisco IOS Security Configuration Guide, Release 12.2. Section: "AAA Overview". (Defining Authentication as the method to identify users and Accounting as the method to track services for billing/auditing).

Internet Engineering Task Force (IETF). RFC 2903 - Generic AAA Architecture. Section 2. (Defines the modular nature of AAA, identifying Authentication as policy enforcement based on identity and Accounting as the collection of resource consumption data).

National Institute of Standards and Technology (NIST). NIST SP 800-12 Rev. 1: An Introduction to Information Security. Chapter 15, "Identification and Authentication". (Provides the standard definition that authentication verifies the identity of a user, process, or device).