CCIE Practical Studies: Security (CCIE Self-Study)

AAA Overview

AAA is a framework that is designed to implement authentication, authorization, and accounting (AAA) in a consistent but modular fashion. You can configure authentication without the use of an external AAA server, such as a Cisco Secure ACS, but if you need to implement a backup authentication method or use one of the security protocols (RADIUS, TACACS+, or Kerberos), you must use the external AAA server.

Detailed configuration of AAA services is covered in Chapter 18, “AAA Services.” Cisco recommends the use of AAA services whenever possible for more granular control of network devices.