Cisco 10000 Series Configuration Manual page 128

Types of QoS Actions
Table 3-4
Action
random-detect dscp dscpvalue min-threshold
max-threshold drop-rate
random-detect exponential-weight-constant
value
Cisco 10000 Series Router Quality of Service Configuration Guide
3-8
Policy Map Actions—Releases Prior to Cisco IOS Release 12.0(17)SL (continued)
Chapter 3 Configuring QoS Policy Actions and Rules
Description
Changes the minimum and maximum packet
thresholds for the differentiated services code point
(DSCP) value.
dscpvalue specifies the DSCP value, which is a
number from 0 to 63, or one of the following
keywords: EF, AFxy, or CS1 through CS7. For more
information, see the "DSCP Per-Hop Behavior"
section on page 7-6.
min-threshold is the minimum threshold. Valid
values are from 32 to 16,384 (PRE1) or 1 to 16,384
(PRE2).
max-threshold is the maximum threshold. Valid
values are from 32 to 16,384 (PRE1) or 1 to 16,384
(PRE2).
drop-rate is the drop probability and is a number
from 1 to 65,535. For example, if you set this value
to 256, 1 out of 256 packets is dropped when the
average queue is at the maximum threshold.
Default values for random-detect vary from
Note
release to release. Use the show policy
interface command to view default values.
Allows you to modify the default method that
random-detect uses to calculate average queue size.
Random-detect determines the average queue size
based on the current queue length and the last
average queue length.
value is a number from 1 to 16. The default value is
typically 9.
The higher the value, the more dependent the
•
average is on the historical average, making
weighted random early detection (WRED) slow
to react to changing traffic conditions that may
be only temporary.
The lower the value, the less dependent the
•
average is on the historical average, making
WRED more sensitive to rapidly changing
traffic conditions.
In most cases, the benefits of WRED can be
Note
best realized if you enter the random-detect
command without arguments.
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