Cisco Systems WSC4500X16SFP Overriding the CoS Priority of Incoming Frames, Configuring Power

28-4
Software Configuration Guide—Release 12.2(25)SG
OL-7659-03
Chapter28 Configuring Voice Interfaces
Overriding the CoS Priority of Incoming Frames
Unknown unicast blocked: disabled
Unknown multicast blocked: disabled
Appliance trust: none
Switch#
Overriding the CoS Priority of Incoming Frames
A PC or another data device can connect to a Cisco 7960 IP phone port. The PC can generate packets
with an assigned CoS value. You can also use the switch CLI to override the priority of frames arriving
on the phone port from connected devices, and you can set the phone port to accept (trust) the priority
of frames arriving on the port.
To override the CoS priority setting received from the non-voice port on the Cisco 7960 IP phon e,
perform this task:
Configuring Power
The Catalyst 4500 series switch senses if it is connected to a Cisco 7960 IP phone. The Catalyst 4500
series switch can supply Power over Ethernet (PoE) to the Cisco 7960 IP phone if there is n o power on
the circuit. The Cisco 7960 IP phone can also be connected to an AC power source and supply its own
power to the voice circuit. If there is power on the circuit, the switch does not supply it.
You can configure the switch not to supply power to the Cisco 7960 IP phone and to disable the detection
mechanism. See the “Enter the show power command to display the current power redundancy and the
current system power usage.” section on page 7-19 for the CLI commands that you can use to supply
PoE to a Cisco 7960 IP phone.
Command Purpose
Step1 Switch# configure terminal Enters configuration mode.
Step2 Switch(config)# interface {fastethernet |
gigabitethernet}
slot / port
Specifies the interface to configure.
Step3 Switch(config-if)# [no] qos trust extend cos 3 Sets 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.
Use the no keyword to return the port to its default setting.
Step4 Switch(config-if)# end Returns to privileged EXEC mode.
Step5 Switch# show interface {fastethernet |
gigabitethernet}
slot/port switchport
Verifies the change.