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1x overview, 1x architecture – H3C Technologies H3C WX3000E Series Wireless Switches User Manual

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802.1X overview

802.1X is a port-based network access control protocol initially proposed by the IEEE 802 LAN/WAN

committee for securing wireless LANs (WLANs), and it has also been widely used on Ethernet networks

for access control.
802.1X controls network access by authenticating the devices connected to 802.1X-enabled LAN ports.

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, as shown in

Figure 52

.

Figure 52 Architecture of 802.1X

The client is 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 is the entity that 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.

Controlled/uncontrolled port and port

authorization status

802.1X defines two logical ports for the network access port: controlled port and uncontrolled port. Any

packet arriving at the network access port is visible to both logical ports.

The controlled port allows incoming and outgoing traffic to pass through when it is in authorized
state, and denies incoming and outgoing traffic when it is in unauthorized state, as shown in

Figure

53

. The controlled port is set in authorized state if the client has passed authentication, and in

unauthorized state, if the client has failed authentication.

The uncontrolled port is always open to receive and transmit EAPOL frames.