Quick Answer

The correct match is 802.1X authentication with RADIUS. This pairing is fundamental because 802.1X is a port-based network access control standard that relies on an Authentication, Authorization, and Accounting (AAA) framework, and RADIUS is the protocol specifically designed to handle the authentication and accounting functions for such network access scenarios. In the ENCOR 350-401 exam, you must distinguish that while RADIUS combines authentication and accounting into a single protocol, TACACS+ separates these services, handling authorization and command authorization separately. A common trap is assuming RADIUS handles all three AAA services equally, but it does not perform authorization for commands—that is TACACS+’s role. This drag-and-drop task tests your ability to map each AAA service to its correct protocol based on real-world Cisco implementations. For a quick memory tip, remember that “RADIUS does the dot1x handshake and the bill,” meaning it authenticates 802.1X users and handles accounting, while “TACACS+ authorizes the commands you can make.”