Security: 802.1X Authentication
Authenticator Overview
Cisco Small Business 200, 300 and 500 Series Managed Switch Administration Guide (Internal Version)  385
19
 
When a port is unauthorized and a guest VLAN is enabled, untagged traffic 
is remapped to the guest VLAN. Tagged traffic is dropped unless it belongs 
to the guest VLAN or to an unauthenticated VLAN. If guest VLAN is not 
enabled on a port, only tagged traffic belonging to unauthenticated VLANs 
is bridged.
When a port is authorized, untagged and tagged traffic from all hosts 
connected to the port is bridged, based on the static VLAN membership 
port configuration.
You can specify that untagged traffic from the authorized port will be 
remapped to a VLAN that is assigned by a RADIUS server during the 
authentication process. Tagged traffic is dropped unless it belongs to the 
RADIUS-assigned VLAN or to the unauthenticated VLANs. Radius VLAN 
assignment on a port is set in the Port Authentication page.
• Multi-Sessions Mode
Unlike the single-host and multi-host modes, a port in the multi-session 
mode does not have an authentication status. This status is assigned to 
each client connected to the port. This mode requires a TCAM lookup. 
Since Layer 3 mode switches (see Multi-Sessions Mode Support) do not 
have a TCAM lookup allocated for multi-sessions mode, they support a 
limited form of multi-sessions mode, which does not support guest VLAN 
and RADIUS VLAN attributes. The maximum number of authorized hosts 
allowed on the port is configured in the Port Authentication page.
Tagged traffic belonging to an unauthenticated VLAN is always bridged 
regardless of whether the host is authorized or not.
Tagged and untagged traffic from unauthorized hosts not belonging to an 
unauthenticated VLAN is remapped to the guest VLAN if it is defined and 
enabled on the VLAN, or is dropped if the guest VLAN is not enabled on the 
port.
If an authorized host is assigned a VLAN by a RADIUS server, all its tagged 
and untagged traffic not belonging to the unauthenticated VLANs is bridged 
via the VLAN; if the VLAN is not assigned, all its traffic is bridged based on 
the static VLAN membership port configuration.