Authentication, authorization, and accounting, (pronounced triple A) provides security to Cisco IOS routers and network devices beyond the simple user authentication available on IOS devices.
AAA provides a method to identify which users are logged into a router and each user's authority level. AAA also provides the capability to monitor user activity and provide accounting information.
In today's IP networks, access to network data is available in a variety of methods, including the following:
PSTN Dialup modems
Access through the Internet through virtual private networks (VPNs)
The AAA model is defined as follows:
Authentication— Who are you?
Authorization— What resources are you ...