Question 278 of 530 from exam 400-251: CCIE Security written exam

Question 278 of 530 from exam 400-251: CCIE Security written exam


Which transport method is used by the IEEE 802.1X protocol?



A. B. C. D.


The IEEE 802.1X protocol is an authentication standard used in local area networks (LANs) to provide secure access control to network devices. It is typically used in conjunction with a Remote Authentication Dial-In User Service (RADIUS) server to authenticate users attempting to access the network.

The transport method used by the IEEE 802.1X protocol is EAPOL frames (Answer A). EAPOL stands for Extensible Authentication Protocol over LAN, which is a protocol used to transport EAP (Extensible Authentication Protocol) packets over LANs.

When a user attempts to access the network, the network access device (such as a switch or wireless access point) sends an EAPOL-Start frame to initiate the authentication process. The client device then responds with an EAPOL-Response frame, which includes an EAP packet containing the user's authentication credentials.

The EAPOL frames are used to transport the EAP packets between the network access device and the client device during the authentication process. Once the user is authenticated, the network access device allows the client device to access the network.

Therefore, option A (EAPOL frames) is the correct answer to the question. Option B (802.3 frames) is incorrect because 802.3 is a standard for Ethernet frames, but not specifically for authentication. Option C (UDP RADIUS datagrams) is incorrect because RADIUS is used as an authentication protocol in conjunction with 802.1X, but it is not the transport method used by the protocol itself. Option D (PPPoE frames) is incorrect because PPPoE is a protocol used to encapsulate PPP frames over Ethernet networks, but it is not specifically used for authentication.