Cisco Certified Internetwork Expert (CCIE) 2025 – 400 Free Practice Questions to Pass the Exam

802.1X is a network access control protocol that is widely used to provide a framework for authenticating devices and users wishing to connect to a network. The protocol establishes an authentication mechanism using a client (the supplicant), a network device (the authenticator), and an authentication server.

In this context, EAP (Extensible Authentication Protocol) plays a crucial role. Specifically, EAP enables the authentication process to be encapsulated within 802.1X frames, allowing various authentication methods to be used seamlessly. The specific variant of EAP used in this layer is often referred to as EAP over LAN (EAPOL). This method allows the client to communicate directly with the authenticator to exchange authentication information.

By utilizing EAP over LAN, the process provides a flexible and efficient way to authenticate users in a network, ensuring that only authorized devices and users gain access. The other protocols mentioned, while significant in different contexts, do not serve the same purpose in the 802.1X authentication process as EAP does. For instance, while RADIUS can be used as an authentication server, the core communication mechanism between the supplicant and authenticator specifically utilizes EAPOL frames to facilitate the authentication dialogue.