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Cisco Catalyst Blade Switch 3130 and 3032 for Dell Software Configuration Guide
OL-12247-04
Chapter 9 Configuring IEEE 802.1x Port-Based Authentication
Understanding IEEE 802.1x Port-Based Authentication
Multidomain Authentication
The switch supports multidomain authentication (MDA), which allows both a data device and voice
device, such as an IP phone (Cisco or non-Cisco), to authenticate on the same switch port. The port is
divided into a data domain and a voice domain.
MDA does not enforce the order of device authentication. However, for best results, we recommend that
a voice device is authenticated before a data device on an MDA-enabled port.
Follow these guidelines for configuring MDA:
•
To configure a switch port for MDA, see the
“Configuring the Host Mode” section on page 9-42
.
•
You must configure the voice VLAN for the IP phone when the host mode is set to multidomain. For
more information, see
Chapter 15, “Configuring Voice VLAN.”
•
Voice VLAN assignment on an MDA-enabled port is supported.
Note
If you use a dynamic VLAN to assign a voice VLAN on an MDA-enabled switch port, 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 is blocked.
•
A voice device MAC address that is binding on the data VLAN is not counted towards the port
security MAC address limit.
•
You can use dynamic VLAN assignment from a RADIUS server only for data devices.
•
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
Authentication Bypass” section on page 9-36
.
•
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 is changed from single- or multihost to multidomain mode, an authorized
data device remains authorized on the port. However, a Cisco IP phone that has been allowed 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- or multihost mode to multidomain mode.
•
Switching a port host mode from multidomain to single- or multihost mode removes all authorized
devices from the port.
