Cisco 4500M User Manual

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Software Configuration Guide—Release 12.2(25)EW
OL-6696-01
Chapter 29 Configuring QoS
Configuring QoS
When configuring the trust state of an interface, note the following:
• You can use the no qos trust command to set the interface state to untrusted.
• For traffic received on an ingress interface configured to trust CoS using the qos trust cos command,
the transmit CoS is always the incoming packet CoS (or the ingress interface default CoS if the
packet is received untagged).
• When the interface trust state is not configured to trust dscp using the qos trust dscp command, the
security and QoS ACL classification will always use the interface DSCP and not the incoming
packet DSCP.
This example shows how to configure Gigabit Ethernet interface 1/1 with the trust cos keywords:
Switch# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Switch(config)# interface gigabitethernet 1/1
Switch(config-if)# qos trust cos
Switch(config-if)# end
Switch#
This example shows how to verify the configuration:
Switch# show qos interface gigabitethernet 1/1 | include trust
Trust state: trust COS
Switch#
Configuring the CoS Value for an Interface
QoS assigns the CoS value specified with this command to untagged frames from ingress interfaces
configured as trusted and to all frames from ingress interfaces configured as untrusted.
To configure the CoS value for an ingress interface, perform this task:
This example shows how to configure the CoS 5 as the default on Fast Ethernet interface 5/24:
Switch# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Switch(config)# interface fastethernet 5/24
Switch(config-if)# qos cos 5
Switch(config-if)# end
Switch#
Command Purpose
Step 1
Switch(config)# interface {fastethernet |
gigabitethernet | tengigabitethernet}
slot/interface | Port-channel number }
Selects the interface to configure.
Step 2
Switch(config-if)# [no] qos cos default_cos
Configures the ingress interface CoS value.
Use the no keyword to clear a configured value and
return to the default.
Step 3
Switch(config-if)# end
Exits configuration mode.
Step 4
Switch# show qos interface {fastethernet |
gigabitethernet | tengigabitethernet}
slot/interface
Verifies the configuration.

Cisco 4500M Specifications

General

Brand	Cisco
Model	4500M
Category	Network Router
Language	English