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Catalyst 6500 Series Switch Cisco IOS Software Configuration Guide—Release 12.1 E
78-14099-04
Chapter 31 Configuring PFC QoS
Configuring PFC QoS
Configuring the Ingress LAN Port CoS Value
Note Whether or not PFC QoS uses the CoS value applied with the mls qos cos command depends on the trust
state of the port and the trust state of the traffic received through the port. The mls qos cos command
does not configure the trust state of the port or the trust state of the traffic received through the port.
To use the CoS value applied with the mls qos cos command as the basis of internal DSCP (see the
“Internal DSCP Values” section on page 31-17):
• On a port that receives only untagged ingress traffic, configure the ingress port as trusted or
configure a trust-CoS policy map that matches the ingress traffic.
• On a port that receives tagged ingress traffic, configure a trust-CoS policy map that matches the
ingress traffic.
You can configure the CoS value that PFC QoS assigns to untagged frames from ingress LAN ports
configured as trusted and to all frames from ingress LAN ports configured as untrusted.
To configure the CoS value for an ingress LAN port, perform this task:
This example shows how to configure the CoS 5 as the default on Fast Ethernet port 5/24 and verify the
configuration:
Router# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)# interface fastethernet 5/24
Router(config-if)# mls qos cos 5
Router(config-if)# end
Router# show queueing interface fastethernet 5/24 | include Default COS
Default COS is 5
Router#
Configuring Standard-Queue Drop Threshold Percentages
These sections describe configuring standard-queue drop threshold percentages:
• Configuring a Tail-Drop Receive Queue, page 31-55
• Configuring a WRED-Drop Transmit Queue, page 31-56
• Configuring a WRED-Drop and Tail-Drop Transmit Queue, page 31-57
• Configuring 1q4t/2q2t Tail-Drop Threshold Percentages, page 31-58
Command Purpose
Step 1 Router(config)# interface {{type1 slot/port} |
{port-channel number}}
1. type = ethernet, fastethernet, gigabitethernet, or tengigabitethernet
Selects the interface to configure.
Step 2 Router(config-if)# mls qos cos default_cos Configures the ingress LAN port CoS value.
Router(config-if)# no mls qos cos default_cos Reverts to the default port CoS value.
Step 3 Router(config-if)# end Exits configuration mode.
Step 4 Router# show queueing interface {ethernet |
fastethernet | gigabitethernet} slot/port
Verifies the configuration.