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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter 29 Configuring QoS
Configuring Standard QoS
To return to the default thresholds, use the no wrr-queue threshold queue-id interface configuration
command. To return to the default DSCP-to-threshold map, use the no wrr-queue dscp-map
[threshold-id] interface configuration command.
This example shows how to configure the tail-drop queue threshold values for queue 1 to 10 percent
and 100 percent, for queue 2 to 40 percent and 100 percent, for queue 3 to 60 percent and 100 percent,
and for queue 4 to 80 percent and 100 percent on the egress interface (Gigabit Ethernet 0/1). The ingress
interface (Gigabit Ethernet 0/2) is configured to trust the DSCP in the incoming packets, to map
DSCPs 0, 8, 16, 24, 32, 40, 48, and 56 to threshold 1, and to map DSCPs 10, 20, 30, 40, 50, and 60 to
threshold 2:
Switch(config)# interface gigabitethernet0/1
Switch(config-if)# switchport mode access
Switch(config-if)# wrr-queue threshold 1 10 100
Switch(config-if)# wrr-queue threshold 2 40 100
Switch(config-if)# wrr-queue threshold 3 60 100
Switch(config-if)# wrr-queue threshold 4 80 100
Switch(config-if)# exit
Switch(config)# interface gigabitethernet0/2
Switch(config-if)# mls qos trust dscp
Switch(config-if)# wrr-queue dscp-map 1 0 8 16 24 32 40 48 56
Switch(config-if)# wrr-queue dscp-map 2 10 20 30 40 50 60
Step 4
wrr-queue threshold queue-id
threshold-percentage1
threshold-percentage2
Configure tail-drop threshold percentages on each egress queue.
The default threshold is 100 percent for thresholds 1 and 2.
•
For queue-id, specify the ID of the egress queue. The range is 1
to 4.
•
For threshold-percentage1 threshold-percentage2, specify the
tail-drop threshold percentage values. Separate each value with a
space. The range is 1 to 100.
Step 5
exit
Return to global configuration mode.
Step 6
interface interface-id
Enter interface configuration mode, and specify the ingress
Gigabit-capable Ethernet interface.
Step 7
wrr-queue dscp-map threshold-id dscp1
... dscp8
Map DSCP values to the tail-drop thresholds of the egress queues.
By default, all DSCP values are mapped to threshold 1.
•
For threshold-id, specify the threshold ID of the queue. The range
is 1 to 2.
•
For dscp1 ... dscp8, specify the DSCP values that are mapped to the
threshold ID. Enter up to eight DSCP values per command.
Separate each value with a space. The range is 0 to 63.
Step 8
end
Return to privileged EXEC mode.
Step 9
show running-config
or
show mls qos interface interface-id
queueing
Verify the DSCP-to-threshold map.
Step 10
show mls qos interface buffers
Verify the thresholds.
Step 11
copy running-config startup-config
(Optional) Save your entries in the configuration file.
Command
Purpose