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Cisco ME 3800X and 3600X Switch Software Configuration Guide
OL-23400-01
Chapter 27 Configuring QoS
Configuring QoS
This example shows how to create a class map called class2, which matches traffic with DSCP values of
10, 11, and 12.
Switch(config)#
class-map match-any class2
Switch(config-cmap)#
match ip dscp 10 11 12
Switch(config-cmap)#
exit
This example shows how to create a class map called class3, which matches traffic with IP-precedence
values of 5, 6, and 7:
Switch(config)#
class-map match-any class3
Switch(config-cmap)#
match ip precedence 5 6 7
Switch(config-cmap)#
exit
This example shows how to create a class-map called parent-class, which matches traffic with VLAN
IDs in the range from 30 to 40.
Switch(config)#
class-map match-any parent-class
Switch(config-cmap)#
match vlan 30-40
Switch(config-cmap)#
exit
Configuring Class-Based-Weighted Fair Queuing
You use the bandwidth policy-map class configuration command to configure class-based weighted fair
queuing (CBWFQ). CBWFQ sets the explicit minimum guaranteed rate (CIR) of a class by reserving the
configured bandwidth for that class.
Follow these guidelines:
•
You can configure CBWFQ at the class level and at the VLAN level.
•
The total of the minimum bandwidth guaranteed for each queue of the policy cannot exceed the total
speed of the parent.
•
You cannot configure bandwidth as an absolute rate or a percentage of total bandwidth when strict
priority is configured for another class in the output policy.
•
You can configure bandwidth as percentage of remaining bandwidth when strict priority is
configured for another class in the output policy map.
•
You cannot configure bandwidth and priority or bandwidth and traffic shaping for the same class in
an output policy map.
Beginning in privileged EXEC mode, follow these steps to use CBWFQ to control bandwidth allocated
to a traffic class by specifying a minimum bandwidth as a bit rate or a percentage:
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
policy-map policy-map-name
Create a policy map by entering the policy map name, and enter
policy-map configuration mode.
Step 3
class {class-map-name | class-default}
Enter a child class-map name or class-default to match all
unclassified packets, and enter policy-map class configuration
mode.
