D-Link DGS-1250 Series Reference Manual page 186

DGS-1250 Series Gigabit Ethernet Smart Managed Switch Web UI Reference Guide
Figure 9-8 The Client
Authentication Process
Utilizing the three roles stated above, the 802.1X protocol provides a stable and secure way of authorizing and
authenticating users attempting to access the network. Only EAPOL traffic is allowed to pass through the specified
port before a successful authentication is made. This port is "locked" until the point when a Client with the correct
username and password (and MAC address if 802.1X is enabled by MAC address) is granted access and therefore
successfully "unlocks" the port. Once the port is unlocked, normal traffic is allowed to pass through the port. The
following figure displays a more detailed explanation of how the authentication process is completed between the
three roles stated above.
Figure 9-9 The 802.1X Authentication Process
The D-Link implementation of 802.1X allows network administrators to use the Port-based Access Control method.
This method requires only one user to be authenticated per port by a remote RADIUS server to allow the remaining
users on the same port access to the network.
Understanding 802.1X Port-based Access Control
The original intent behind the development of 802.1X was to leverage the characteristics of point-to-point in LANs. As
any single LAN segment in such infrastructures has no more than two devices attached to it, one of which is a Bridge
Port. The Bridge Port detects events that indicate the attachment of an active device at the remote end of the link, or
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