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Cisco ME 3400 Ethernet Access Switch Software Configuration Guide
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Chapter 33 Configuring QoS
Configuring QoS
Beginning in privileged EXEC mode, follow these steps to use WTD to adjust the queue size for a traffic
class:
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.
• If you enter a class-map name, you must perform Step 4 to
configure a scheduling action (bandwidth, shape average,
or priority) before you go to Step 5 to configure queue-limit.
• If you enter class-default, you can skip Step 4.
Step 4
bandwidth {rate | percent value | remaining
percent value}
or
shape average target bps
or
priority
Configure a scheduling action for the traffic class. For more
information, see the
“Configuring Output Policy Maps with
Class-Based-Weighted-Queuing” section on page 33-53, the
“Configuring Output Policy Maps with Class-Based Shaping”
section on page 33-54, the “Configuring Output Policy Maps with
Port Shaping” section on page 33-56, or the “Configuring Output
Policy Maps with Class-Based Priority Queuing” section on
page 33-57.
Step 5
queue-limit [cos value | dscp value | precedence
value | qos-group value] number-of-packets
[packets]}
Specify the queue size for the traffic class.
• (Optional) For cos value, specify a CoS value. The range is
from 0 to 7.
• (Optional) For dscp value, specify a DSCP value. The range
is from 0 to 63.
• (Optional) For precedence value, specify an IP precedence
value. The range is from 0 to 7.
• (Optional) For qos-group value, enter a QoS group value.
The range is from 0 to 99.
• For number-of-packets, set the minimum threshold for WTD.
The range is from 16 to 544, in multiples of 16, where each
packet is a fixed unit of 256 bytes.
Note For optimal performance, we strongly recommend that
you configure the queue-limit to 272 or less.
The value is specified in packets by default, but the packets
keyword is optional.
Note Multiple output policy maps can use the same queue-limit
configuration. However these policy maps can have only
three unique queue-limit configurations.
Step 6
exit Return to policy-map configuration mode.
Step 7
exit Return to global configuration mode.
