Cisco Catalyst 3750 - Page 572

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Catalyst 3750 Metro Switch Software Configuration Guide
78-15870-01
Chapter 26 Configuring QoS
Configuring Hierarchical QoS
To delete an existing policy map, use the no policy-map policy-map-name global configuration
command. To delete an existing class, use the no class class-name policy-map configuration command.
To return to the default bandwidth, use the no bandwidth policy-map class configuration command. To
disable DSCP-based WRED, use the no random-detect dscp-based policy-map class configuration
command. To return to the default WRED settings, use the no random-detect dscp dscp policy-map
class configuration command.
This example shows how to configure a class-level policy called policy10. Class c1 has these
characteristics: a minimum of 2000 kbps of bandwidth is expected to be delivered to this class in the
event of congestion, and a weight factor of 10 is used to calculate the average queue size. To avoid
congestion, DSCP-based WRED packet drop is used instead of tail drop. The minimum threshold for
DSCP value 8 is 24, the maximum threshold is 40, and the mark-probability denominator is 512.
Switch(config)# class-map c1
Switch(config-cmap)# match ip dscp 8
Switch(config-cmap)# exit
Switch(config)# policy-map policy10
Switch(config-pmap)# class c1
Switch(config-pmap-c)# bandwidth 2000
Switch(config-pmap-c)# random-detect dscp-based
Switch(config-pmap-c)# random-detect exponential-weighting-constant 10
Switch(config-pmap-c)# random-detect dscp 8 24 40 512
Switch(config-pmap-c)# exit
Switch(config-pmap)# exit
Switch(config)# interface gigabitethernet1/1/1
Switch(config-if)# switchport trunk encapsulation isl
Switch(config-if)# switchport mode trunk
Switch(config-if)# service-policy output policy10
Step 7
random-detect
exponential-weighting-constant weight
(Optional) Configure the exponential weight factor for the average
queue-size calculation for WRED. The range is 1 to 16. The default
is 9.
Step 8
exit Return to policy-map configuration mode.
Step 9
exit Return to global configuration mode.
Step 10
interface interface-id Specify an ES port to attach to the policy map, and enter interface
configuration mode.
Step 11
service-policy output policy-map-name Specify the egress policy-map name, and apply it to the ES port.
Only one policy map per port is supported.
Step 12
end Return to privileged EXEC mode.
Step 13
show policy-map [policy-map-name [class
class-map-name]]
or
show policy-map interface interface-id
Verify your entries.
Step 14
copy running-config startup-config (Optional) Save your entries in the configuration file.
Command Purpose