When you configure a guest VLAN, clients that are not 802.1x-capable are put into the guest VLAN when the server does not receive a response to its EAPOL request/identity frame. Clients that are 802.1x-capable but fail authentication are not granted access to the network. The switch supports guest VLANs in single-host or multiple-hosts mode.
The guest vlan is supported on these switches:
Catalyst 29XX series switches
Catalyst 35XX series switches
Catalyst 3750 series switches
Catalyst 4500 series switches
Catalyst 6500 running CatOS system software
Note: Catalyst 6500 running Cisco IOS or Native platform does not support guest VLAN and auth-fail VLAN as for now.