This read-write field defines a fallback VLAN ID to assign when RADIUS's Access-Accept message doesn't itself include a VLAN attribute, active only when set to a non-zero value. An administrator configures this as a default VLAN for authenticated sessions whose RADIUS policy doesn't specify one explicitly. For example, setting this OID to a standard employee VLAN ensures that any successfully authenticated user without a RADIUS-assigned VLAN attribute still lands there rather than being left unassigned.