Dell PowerSwitch S4820T Configuration Guide for the S4820T System 9.112.0P1 - Page 86

• Configuring dot1x Profile • Configuring the Static MAB and MAB Profile • Configuring Critical VLAN Port-Authentication Process The 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 Request frame. 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 frame and forwards the frame to the authentication server. 4 The authentication server replies with an Access-Challenge frame. The Access-Challenge frame requests the supplicant to prove that it is who it claims to be, using a specified method (an EAP-Method). The challenge is translated and forwarded to the supplicant by the authenticator. 5 The supplicant can negotiate the authentication method, but if it is acceptable, the supplicant provides the Requested Challenge information in an EAP response, which is translated and forwarded to the authentication server as another Access-Request frame. 6 If the identity information provided by the supplicant is valid, the authentication server sends an Access-Accept frame in which network privileges are specified. The authenticator changes the port state to authorized and forwards an EAP Success frame. If the identity information is invalid, the server sends an Access-Reject frame. If the port state remains unauthorized, the authenticator forwards an EAP Failure frame. Figure 5. EAP Port-Authentication EAP over RADIUS 802.1X uses RADIUS to shuttle EAP packets between the authenticator and the authentication server, as defined in RFC 3579. EAP messages are encapsulated in RADIUS packets as a type of attribute in Type, Length, Value (TLV) format. The Type value for EAP messages is 79. 86 802.1X