11-28
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 IP Precedence
To drop packets based on IP precedence, enter the following commands beginning in global
configuration mode:
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
PRE2
Router(config-pmap-c)#
random-detect
precedence-based
PRE3
Router(config-pmap-c)#
random-detect
precedence-based
aggregate
[
minimum-thresh
min-thresh
maximum-thresh
max-thresh
mark-prob
mark-prob
]
Indicates that weighted random early detection (WRED) is to use
the IP precedence of a packet when calculating the packet drop
probability.
(Optional)
min-thresh
is the minimum number of packets allowed
in the queue. Valid minimum threshold values are from 1 to
16,384.
(Optional)
max-thresh
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-prob
is the drop rate. Valid values are from 1 to
65,535. The default value is 10.
Step 4
Router(config-pmap-c)#
random-detect
precedence
prec-value min-thresh-value
max-thresh-value
mark-probability-denominator-value
PRE3
Router(config-pmap-c)#
random-detect
precedence values
s
ub-class-val
1
[...[
sub-class-val8
]]
minimum-thresh
min-thresh
maximum-thresh
max-thresh
mark-prob
mark-prob
Configures WRED to drop packets based on the IP precedence
value you specify.
prec-value
(PRE2) or
values
sub-class-val
(PRE3) is a number
that identifies the IP precedence level. Valid values are from 0 to
7.
min-thresh
is the minimum number of packets allowed in the
queue. Valid minimum threshold values are from 1 to 16,384.
max-thresh
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.
mark-probability-denominator-value
(PRE2) or
mark-prob
(PRE3) is the drop rate. Valid values are from 1 to 65,535. The
default value is 10.