10-14
Catalyst 2960 and 2960-S Switch Software Configuration Guide
OL-8603-09
Chapter 10 Configuring IEEE 802.1x Port-Based Authentication
Understanding IEEE 802.1x Port-Based Authentication
• Voice VLAN assignment on an MDA-enabled port is supported in Cisco IOS Release 12.2(40)SE
and later.
Note If you use a dynamic VLAN to assign a voice VLAN on an MDA-enabled switch port on a swi tch
running Cisco IOS Release 12.2(37)SE, the voice device fails authorization.
• To authorize a voice device, the AAA server must be configured to send a Cisco Attribute-Value
(AV) pair attribute with a value of device-traffic-class=voice. Without this value, the switch
treats the voice device as a data device.
• The guest VLAN and restricted VLAN features only apply to the data devices on an MDA-enabled
port. The switch treats a voice device that fails authorization as a data device.
• If more than one device attempts authorization on either the voice or the data domain of a port, it is
error disabled.
• Until a device is authorized, the port drops its traffic. Non-Cisco IP phones or voice devices are
allowed into both the data and voice VLANs. The data VLAN allows the voice device to contact a
DHCP server to obtain an IP address and acquire the voice VLAN information. After the voice
device starts sending on the voice VLAN, its access to the data VLAN i s blocked.
• A voice device MAC address that is binding on the data VLAN is not counted t owards the port
security MAC address limit.
• MDA can use MAC authentication bypass as a fallback mechanism to allow the switch port to
connect to devices that do not support 802.1x authentication. For more information, see the “MAC
Authentication Bypass” section on page 10-40.
• When a data or a voice device is detected on a port, its MAC address is blocked until authorization
succeeds. If the authorization fails, the MAC address remains blocked for 5 minutes.
• If more than five devices are detected on the data VLAN or more than one voice device is detected
on the voice VLAN while a port is unauthorized, the port is error disabled.
• When a port host mode changes from single- or multihost to multidomain mode, an authorized data
device remains authorized on the port. However, a Cisco IP phone on the port voice VLAN is
automatically removed and must be reauthenticated on that port.
• Active fallback mechanisms such as guest VLAN and restricted VLAN remain configured after a
port changes from single-host or multiple-host mode to multidom ain mode.
• Switching a port host mode from multidomain to single-host or multiple-hosts mode removes all
authorized devices from the port.
• If a data domain is authorized first and placed in the guest VLAN, non-802.1x-capable voice devices
need their packets tagged on the voice VLAN to trigger authentication. The phone need not need to
send tagged traffic. (The same is true for an 802.1x-capable phone.)
• We do not recommend per-user ACLs with an MDA-enabled port. An authorized device wi th a
per-user ACL policy might impact traffic on both the port voice and data VLANs. You can use only
one device on the port to enforce per-user ACLs.
For more information, see the “Configuring the Host Mode” section on page 10-46.