Which two protocols are used to provide server-based AAA authentication? (Choose two.)

The two protocols used to provide server-based AAA (Authentication, Authorization, and Accounting) authentication are:

1. TACACS+ (Terminal Access Controller Access-Control System Plus)
2. RADIUS (Remote Authentication Dial-In User Service)

These protocols are specifically designed for managing network access control and are widely used for their robust security features. TACACS+ is commonly used in Cisco environments, while RADIUS is more broadly used across various network equipment and scenarios.