Cisco Systems ME 3400

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Cisco ME 3400 Ethernet Access Switch Software Configuration Guide

OL-9639-06

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}

shape average target bps

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.