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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter20 Co nf iguring QoS
Configuring QoS
To return a port to its non-trusted state, use the no mls qos trust interface configuration command. To
return to the default DSCP-to-DSCP-mutation map values, use the no mls qos map dscp-mutation
dscp-mutation-map-name global configuration command.
This example shows how to configure Gigabit Ethernet port 0/2 to the DSCP-trusted state and to modify
the DSCP-to-DSCP-mutation map (named gi0/2-mutation) so that incoming DSCP values 10 to 13 are
mapped to DSCP values 30 to 33:
Switch# configure terminal
Switch(config)# mls qos map dscp-mutation gi0/2-mutation 10 11 12 13 to 30 31 32 33
Switch(config)# interface gigabitethernet0/2
Switch(config-if)# mls qos trust dscp
Switch(config-if)# mls qos dscp-mutation gi0/2-mutation
Switch(config-if)# end
Configuring a QoS Policy
Configuring a QoS policy typically requires classifying traffic into classes, configuring polici es applied
to those traffic classes, and attaching policies to interfaces.
For background information, see the “Classification” section on page 20-4 and the “Policing and
Marking” section on page 20-8 .
This section contains this configuration information:
•Classifying Traffic by Using ACLs, page 20-27
•Classifying Traffic by Using Class Maps, page 20-30
•Classifying, Policing, and Marking Traffic by Using Policy Maps, page 20-32
•Classifying, Policing, and Marking Traffic by Using Aggregate Policers, page 20-37
Step6 mls qos dscp-mutation
dscp-mutation-name Apply the map to the specified ingress DSCP-trusted port.
You can apply the map to different Gigabit-capable Ethernet ports.
However, on 10/100 Ethernet ports, you can attach only one
DSCP-to-DSCP-mutation map to a group of twelve ports. For example,
Fast Ethernet ports 0/1 to 0/12 are a group, Fast Ethernet ports 0/13 to
0/24 are a group, Gigabit Ethernet 0/1 is a group, and Gigabit Ethernet
0/2 is a group. When applying a mutation map to any po rt i n a gr oup ,
all ports in the same group are automatically configured with the same
map.
Step7 end Return to privileged EXEC mode.
Step8 show mls qos maps dscp-mutation Verify your entries.
Step9 copy running-config startup-config (Optional) Save your entries in the configuration file.
Command Purpose