Cisco Systems EA6500 Manual De Usuario

Untagged traffic from the device attached to the Cisco IP Phone passes through the Cisco IP Phone 
unchanged, regardless of the trust state of the access port on the Cisco IP Phone.

To process tagged data traffic (traffic in 802.1Q or 802.1p frame types) from the device attached to the 
access port on the Cisco IP Phone (see 

), you can configure Layer 2 access ports on the 

switch to send CDPv2 packets that instruct an attached Cisco IP Phone to configure the access port on 
the Cisco IP Phone to either of these two modes:

Trusted mode—All traffic received through the access port on the Cisco IP Phone passes through 
the Cisco IP Phone unchanged. 

Untrusted mode—All traffic in 802.1Q or 802.1p frames received through the access port on the 
Cisco IP Phone is marked with a configured Layer 2 CoS value. The default Layer 2 CoS value is 0. 
Untrusted mode is the default.

These sections describe Cisco IP Phone power configurations:

There are two varieties of local power:

From a power supply connected to the Cisco IP Phone 

From a power supply through a patch panel over the twisted-pair Ethernet cable to the 
Cisco IP Phone

When a locally powered Cisco IP Phone is present on a switching module port, the switching module 
cannot detect its presence. The supervisor engine discovers the Cisco IP Phone through CDPv2 
messaging with the Cisco IP Phone.

If a locally powered Cisco IP Phone loses local power and the mode is set to auto, the switching module 
discovers the Cisco IP Phone and informs the supervisor engine, which then supplies inline power to the 
Cisco IP Phone.

Inline power is from switching modules that support an inline power daughtercard. Inline power is sent 
over the twisted-pair Ethernet cable to the Cisco IP Phone. 

For information about switching modules that support inline power, refer to the Release Notes for Cisco 
IOS Release 12.1E on the Catalyst 6000 and Cisco 7600 Supervisor Engine and MSFC publication at 
this URL: