Figure 8. EAP Frames Encapsulated in Ethernet and RADUISThe authentication process involves three devices:• The device attempting to access the network is the supplicant. The supplicant is not allowed to communicate on the networkuntil the authenticator authorizes the port. It can only communicate with the authenticator in response to 802.1X requests.• The device with which the supplicant communicates is the authenticator. The authenticator is the gate keeper of the network.It translates and forwards requests and responses between the authentication server and the supplicant. The authenticator alsochanges the status of the port based on the results of the authentication process. The Dell Networking switch is theauthenticator.• The authentication-server selects the authentication method, verifies the information the supplicant provides, and grants itnetwork access privileges.Ports can be in one of two states:• Ports are in an unauthorized state by default. In this state, non-802.1X traffic cannot be forwarded in or out of the port.• The authenticator changes the port state to authorized if the server can authenticate the supplicant. In this state, networktraffic can be forwarded normally.NOTE: The Dell Networking switches place 802.1X-enabled ports in the unauthorized state by default.Port-Authentication ProcessThe authentication process begins when the authenticator senses that a link status has changed from down to up:1. When the authenticator senses a link state change, it requests that the supplicant identify itself using an EAP Identity Requestframe.2. The supplicant responds with its identity in an EAP Response Identity frame.3. The authenticator decapsulates the EAP response from the EAPOL frame, encapsulates it in a RADIUS Access-Request frameand forwards the frame to the authentication server.4. The authentication server replies with an Access-Challenge frame. The Access-Challenge frame requests the supplicant toprove that it is who it claims to be, using a specified method (an EAP-Method). The challenge is translated and forwarded tothe supplicant by the authenticator.5. The supplicant can negotiate the authentication method, but if it is acceptable, the supplicant provides the RequestedChallenge information in an EAP response, which is translated and forwarded to the authentication server as another Access-Request frame.94 802.1X
