Cisco ME 3600X, Command Reference Manual

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Cisco ME 3800X and ME 3600X Switch Command Reference
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Chapter 2 Cisco ME 3800X and ME 3600X Switch Cisco IOS Commands
random-detect
Two Methods for Calculating the Drop Probability of a Packet
This command includes two optional keywords, dscp-based and prec-based , that determine the method
WRED uses to calculate the drop probability of a packet.
Note the following points when deciding which method to instruct WRED to use:
• With the dscp-based keyword, WRED uses the DSCP value (that is, the first six bits of the IP type
of service (ToS) byte) to calculate the drop probability.
•
With the prec-based keyword, WRED will use the IP Precedence value to calculate the drop
probability.
• The dscp-based and prec-based keywords are mutually exclusive.
•
If neither argument is specified, WRED uses the IP Precedence value to calculate the drop
probability (the default method).
Examples The following example configures the policy map called policy1 to contain policy specification for the
class called class1. During times of congestion, WRED packet drop is used instead of tail drop.
! The following commands create the class map called class1:
class-map class1
match input-interface fastethernet0/1
! The following commands define policy1 to contain policy specification for class1:
policy-map policy1
class class1
bandwidth 1000
random-detect
The following example enables WRED to use the DSCP value 8. The minimum threshold for the DSCP
value 8 is 24 and the maximum threshold is 40. This configuration was performed at the interface level.
Switch(config)# interface serial0/0
Switch(config-if)# random-detect dscp-based
Switch(config-if)# random-detect dscp 8 24 40
The following example enables WRED to use the DSCP value 8 for class c1. The minimum threshold
for DSCP value 8 is 24 and the maximum threshold is 40. The last line attaches the service policy to the
output interface or virtual circuit (VC) p1.
Switch(config-if)# class-map c1
Switch(config-cmap)# match access-group 101
Switch(config-if)# policy-map p1
Switch(config-pmap)# class c1
Switch(config-pmap-c)# bandwidth 48
Switch(config-pmap-c)# random-detect dscp-based
Switch(config-pmap-c)# random-detect dscp 8 24 40
Switch(config-pmap-c)# exit
Switch(config-pmap)# exit
Switch(config)# interface serial0/0
Switch(config-if)# service-policy output p1
Related Commands Command Description
random-detect dscp Changes the minimum and maximum packet thresholds for the
DSCP value.