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Cisco 10000 Series Router Quality of Service Configuration Guide
OL-7433-09
Chapter 11 Managing Packet Queue Congestion
Configuring Layer 3 Queue Limit and Drop Policies
Dropping Packets Based on the ATM Cell Loss Priority
To drop packets based on the ATM cell loss priority (CLP), enter the following commands beginning in
global configuration mode:
Note
Dropping packets based on the CLP requires the PRE3 and Cisco IOS Release 12.2(33)SB, or a later
release.
Configuration Example for Dropping Packets Based on the Cell Loss Priority
Example 11-5
shows how to configure ATM CLP-based WRED. In the example, traffic that matches
CLP 1 is classified as belonging to class1. In the policy map named policymap1, the class1 configuration
enables the ATM CLP-based WRED feature and configures WRED to randomly drop traffic with the
CLP bit set to 1 when traffic exceeds the minimum threshold of 12 and the maximum threshold of 25.
WRED uses a mark-probability-denominator of 10.
Example 11-5
Configuring CLP-Based WRED
Router(config)#
class-map class1
Router(config-cmap)#
match clp 1
Router(config-cmap)#
exit
Router(config)#
policy-map policymap1
Command
Purpose
Step 1
Router(config)#
policy-map
policy-map-name
Specifies the name of the policy map to be created or modified.
Enters policy-map configuration mode.
policy-map-name
is the name of the policy map.
Step 2
Router(config-pmap)#
class
class-map-name
Assigns the traffic class you specify to the policy map. Enters
policy-map class configuration mode.
class-map-name
is the name of a previously configured class map
and is the traffic class for which you want to define QoS actions.
Step 3
Router(config-pmap-c)#
random-detect
atm-clp-based
Indicates that weighted random early detection (WRED) is to use
the CLP value of a packet when calculating the packet drop
probability.
Step 4
Router(config-pmap-c)#
random-detect clp
[
clp-value
] [
min-thresh-value
]
[
max-thresh-value
]
[
mark-probability-denominator-value
]
Configures WRED to drop packets based on the CLP value you
specify.
clp-value
is a number that indicates the cell loss priority of a
packet. Valid values are 0 or 1.
(Optional)
min-thresh-value
is the minimum number of packets
allowed in the queue. Valid minimum threshold values are from 1
to 16,384.
(Optional)
max-thresh-value
is the maximum number of packets
allowed in the queue. Valid maximum threshold values are from
the value of the minimum threshold to 16,384.
(Optional)
mark-probability-denominator-value
is the drop rate.
Valid values are from 1 to 65,535. The default value is 10.
