Security
Configuring 802.1X
395 Cisco 500 Series Stackable Managed Switch Administration Guide Release 1.3
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- Single session/multiple hosts—This follows the 802.1x standard. In this 
mode, the device as an authenticator allows any device to use a port as 
long as it has been granted permission. 
• Multi-Session 802.1X—Every device (supplicant) connecting to a port 
must be authenticated and authorized by the device (authenticator) 
separately in a different 802.1x session. 
NOTE This is the only mode that supports Dynamic VLAN Assignment (DVA). 
Dynamic VLAN Assignment (DVA)
Dynamic VLAN Assignment (DVA) is also referred to as RADIUS VLAN Assignment 
in this guide. When a port is in Multiple Session mode and is DVA-enabled, the 
device automatically adds the port as an untagged member of the VLAN that is 
assigned by the RADIUS server during the authentication process. The device 
classifies untagged packets to the assigned VLAN if the packets originated from 
the devices or ports that are authenticated and authorized.
NOTE DVA is only supported on the Sx500 model switches when the device is in Layer 2 
system mode.
For a device to be authenticated and authorized at a port which is DVA-enabled:
• The RADIUS server must authenticate the device and dynamically assign a 
VLAN to the device. The user can configure an alternative VLAN ahead of 
time to be used if the RADIUS server does not assign a VLAN.
• The assigned VLAN must not be the default VLAN and must have been 
created on the device. 
• The device must not be configured to use both a DVA and a MAC-based 
VLAN group together. 
• A RADIUS server must support DVA with RADIUS attributes tunnel-type 
(64) = VLAN (13), tunnel-media-type (65) = 802 (6), and tunnel-private-
group-id = a VLAN ID.
The authentication methods can be:
• 802.1x—The device supports the authentication mechanism, as described 
in the standard, to authenticate and authorize 802.1x supplicants.
• MAC-based—The device can be configured to use this mode to 
authenticate and authorized devices that do not support 802.1x. The device 
emulates the supplicant role on behalf of the non 802.1x capable devices, 
and uses the MAC address of the devices as the username and password 
when communicating with the RADIUS servers. MAC addresses for