TCP/IP Tutorial and Technical Overview - IBM Redbooks

802.1x authentication process
The authentication process illustrated in Figure 23-5 depicts the basic
step-by-step process of 802.1x authentication of endpoint devices (for example,
workstations).
Step1 Step 2
Network
Supplicant
(end user)
Figure 23-5 Authentication process
From the authentication process shown in Figure 23-5:
1. A workstation is attached to the network, and the supplicant initiates a
session with the authenticator. The session is initiated by sending an
EAPoL-Start packet. The authenticator responds by sending an
EAP-Request/Identity packet to the supplicant. The network port can directly
initiate the authentication process by sending an EAP-Request/Identity
packet to the supplicant as soon as the port has become operable with
authentication enabled on it.
2. The supplicant provides its identity by responding to the authenticator with an
EAP-Response/Identity packet. The authenticator forwards this EAP packet
to the authentication server over RADIUS, which verifies the supplicant's
identity.
896 TCP/IP Tutorial and Technical Overview
Step 3 Steps 4, 5 (failure)
Authenticator
Unauthorized Access Authorized Access
Authentication Services
Authentication
Server
Step 6
LDAP