802.1X architecture
802.1X operates in the client/server model. It comprises three entities: the client (the supplicant), the network access device (the authenticator), and the authentication server.
Figure 23: 802.1X architecture
The client—A user terminal seeking access to the LAN. It must have 802.1X software to authenticate to the network access device.
The network access device—Authenticates the client to control access to the LAN. In a typical 802.1X environment, the network access device uses an authentication server to perform authentication.
The authentication server—Provides authentication services for the network access device. It authenticates 802.1X clients by using the data sent from the network access device, and returns the authentication results for the network access device to make access decisions. The authentication server is typically a Remote Authentication Dial-in User Service (RADIUS) server. In a small LAN, you can also use the network access device as the authentication server.