Configuring A Port To Connect To A Cisco Ip Phone; Overriding The Cos Priority Of Incoming Frames - Cisco WS-C2955T-12 Software Manual

Configuring Voice Ports

Configuring a Port to Connect to a Cisco IP Phone

Because a Cisco IP Phone also supports connection to a PC or other device, a port connecting a
Catalyst 3524-PWR XL switch to a Cisco IP Phone can carry mixed traffic. There are three
configurations for a port connected to a Cisco IP Phone:
•
•
•
Beginning in privileged EXEC mode, follow these steps to configure a port to instruct the phone to give
voice traffic a higher priority and to forward all traffic through the 802.1Q native VLAN:
Command
Step 1
configure terminal
Step 2
interface interface
Step 3 switchport voice vlan dot1p
Step 4 end
Step 5 show interface interface switchport

Overriding the CoS Priority of Incoming Frames

A PC or other data device can connect to a Cisco IP Phone port. The PC can generate packets with an
assigned CoS value. If you want, you can use the Catalyst 3524-PWR XL CLI to override the priority of
frames arriving on the phone port from connected devices. You can also set the phone port to accept
(trust) the priority of frames arriving on the port.
Beginning in privileged EXEC mode, follow these steps to override the CoS priority setting received
from the nonvoice port on the Cisco IP Phone:
Command
Step 1 configure terminal
Step 2
interface interface
Step 3
switchport priority extend
cos 3
Step 4
end
Step 5
show interface interface switchport
Use the no switchport priority extend command to return the port to its default setting.
Catalyst 2900 Series XL and Catalyst 3500 Series XL Software Configuration Guide
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All traffic is sent according to the default COS priority of the port. This is the default.
Voice traffic is given a higher priority by the phone, and all traffic is in the same VLAN.
Voice and data traffic are carried on separate VLANs, and voice traffic always has a CoS priority
of 5.
Purpose
Enter global configuration mode.
Enter interface configuration mode, and enter the port to be configured.
Instruct the switch port to use 802.1p priority tagging for voice traffic and to
use VLAN 0 (default native VLAN) to carry all traffic.
Return to privileged EXEC mode.
Verify the port configuration.
Purpose
Enter global configuration mode.
Enter interface configuration mode, and enter the switch port to be
configured.
Set the phone port to override the priority received from the PC or the
attached device and forward the received data with a priority of 3.
Return to privileged EXEC mode.
Verify the change.
Chapter 7 Configuring the Switch Ports
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