Active Queue Management (Aqm) Via Dynamic Buffer Limiting (Dbl) - Cisco Catalyst 4500 Series Configuration Manual

Chapter 40 Configuring Quality of Service
Switch(config-if)# end
Switch#
Switch# show policy-map policy1
Policy Map policy1
Switch#

Active Queue Management (AQM) via Dynamic Buffer Limiting (DBL)

AQM provides buffering control of traffic flows prior to queuing a packet into a transmit queue of a port.
This is of significant interest in a shared memory switch, ensuring that certain flows do not hog the
switch packet memory.
Note The supervisor engine supports active switch buffer management via DBL.
Except for the default class of traffic (class class-default), you can configure DBL action only when at
least one of the other queuing action is configured.
To configure class-level dbl action along with shaping in a service policy, perform this task:
Command
Step 1
Switch# configure terminal
Step 2
Switch(config)# policy-map
policy-map-name
Step 3
Switch(config-pmap)# class class-name
Step 4
Switch(config-pmap-class)# shape
average cir-bps
Step 5
Switch(config-pmap-class)# dbl
Step 6
Switch(config-pmap-class)# exit
Step 7
Switch(config-pmap)# exit
Step 8
Switch(config)# interface interface-id
Step 9
Switch(config-interface)#
service-policy output policy-map-name
Step 10
Switch(config-interface)# end
OL-25340-01
Class class1
shape average 256000
queue-limit 4048
Purpose
Enters global configuration mode.
Creates a policy map by entering the policy-map name, and enter
policy-map configuration mode.
By default, no policy maps are defined.
Specifies the name of the class whose traffic policy you want to
create or change, and enter policy-map class configuration mode.
By default, no traffic classes are defined.
Enables average-rate traffic shaping.
Specify the committed information rate, the bit rate that traffic is
shaped to, in bps. The range is 32000 to 10000000000 bps.
By default, average-rate traffic shaping is disabled.
Enables DBL on the queue associated with this class of traffic
Returns to policy-map configuration mode.
Returns to global configuration mode.
Specifies a physical port and enter interface configuration mode.
Specifies the policy-map name, and apply it a physical interface.
Returns to privileged EXEC mode.
Software Configuration Guide—Release IOS XE 3.3.0SG and IOS 15.1(1)SG
Configuring QoS
40-33