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Catalyst 3750 Metro Switch Command Reference
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Chapter 2 Catalyst 3750 Metro Switch Cisco IOS Commands
random-detect exponential-weighting-constant
random-detect exponential-weighting-constant
Use the
random-detect exponential-weighting-constant
policy-map class configuration command to
configure Weighted Random Early Detection (WRED) exponential weight factor for the average
queue-size calculation for the queue in a hierarchical policy map attached to an enhanced-services (ES)
port. Use the
no
form of this command to return to the default settings.
random-detect
exponential-weighting-constant
weight
no random detect exponential-weighting-constant
Syntax Description
Defaults
The default is 9.
Command Modes
Policy-map class configuration
Command History
Usage Guidelines
WRED is a congestion-avoidance mechanism that slows traffic by randomly dropping packets when
congestion exists. WRED reduces the chances of tail drop by selectively dropping packets when the
egress port begins to show signs of congestion. By dropping some packets early rather than waiting until
the queue is full, WRED does not drop large numbers of packets at once.
Use the
random-detect exponential-weighting-constant
command only in a hierarchical policy map
attached to an ES port. You can use this command only in class-level classes.
You must configure the
bandwidth
or the
shape
policy-map class configuration command before you
configure either the
queue-limit
or the
random-detect
policy-map class configuration command in a
class policy.
You can define a class policy to use either tail drop or WRED packet drop by using either the
queue-limit
policy-map class configuration command or the
random-detect
policy-map class configuration
command, respectively. You cannot use the
queue-limit
and
random-detect
commands in the same
class policy, but they can be used in two class policies in the same policy map.
You cannot use the
bandwidth
,
queue-limit
,
random-detect
, and the
shape
policy-map class
configuration commands with the
priority
policy-map class configuration command in the same class
within the same policy map. However, you can use these commands in the same policy map.
weight
Configure the exponential weight factor for the average queue-size
calculation for WRED. The range is 1 to 16.
Release
Modification
12.1(14)AX
This command was introduced.
12.2(25)EY
Hierarchical service policies can be attached to inbound traffic received on
an ES port.
