Configuring Port-Based and User-Based Access Control (802.1X)

How RADIUS/802.1X Authentication Affects VLAN Operation

If the port is assigned as a member of an untagged dynamic VLAN that was learned through GVRP, the dynamic VLAN configuration must exist on the switch at the time of authentication and GVRP- learned dynamic VLANs for port-access authentication must be enabled.

If the dynamic VLAN does not exist or if you have not enabled the use of a dynamic VLAN for authentication sessions on the switch, the authentication fails.

To enable the use of a GVRP-learned (dynamic) VLAN as the untagged VLAN used in an authentication session, enter the aaa port-access gvrp- vlans command, as described in “Enabling the Use of GVRP-Learned Dynamic VLANs in Authentication Sessions” on page 10-71.

Enabling the use of dynamic VLANs in an authentication session offers the following benefits:

You avoid the need of having static VLANs pre-configured on the switch.

You can centralize the administration of user accounts (including user VLAN IDs) on a RADIUS server.

For information on how to enable the switch to dynamically create 802.1Q-compliant VLANs on links to other devices using the GARP VLAN Registration Protocol (GVRP), see the chapter on “GVRP” in the Advanced Traffic Management Guide.

For an authentication session to proceed, a port must be an untagged member of the (static or dynamic) VLAN assigned by the RADIUS server (or an authorized-client VLAN configuration). The port temporarily drops any current untagged VLAN membership.

If the port is not already a member of the RADIUS-assigned (static or dynamic) untagged VLAN, the switch temporarily reassigns the port as an untagged member of the required VLAN (for the duration of the session). At the same time, if the port is already configured as an untagged member of a different VLAN, the port loses access to the other VLAN for the duration of the session. (A port can be an untagged member of only one VLAN at a time.)

When the authentication session ends, the switch removes the temporary untagged VLAN assignment and re-activates the temporarily disabled, untagged VLAN assignment.

If GVRP is already enabled on the switch, the temporary untagged (static or dynamic) VLAN created on the port for the authentication session is advertised as an existing VLAN.

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