Filter
Top Products
37-84
Software Configuration Guide—Release 15.0(2)SG
OL-23818-01
Chapter 37 Configuring Quality of Service
Configuring QoS on Supervisor Engine 6-E, Supervisor Engine 6L-E, Catalyst 4900M, and Catalyst 4948E
This example shows how to configure a class-based queue with an explicit queue-limit command. It
limits traffic class class1 to a queue of size 4048:
Switch# configure terminal
Switch(config)# policy-map policy1
Switch(config-pmap)# class class1
Switch(config-pmap-c)# shape average 256000
Switch(config-pmap-c)# queue-limit 4048
Switch(config-pmap-c)# exit
Switch(config-pmap)# exit
Switch(config)# interface gigabitethernet1/1
Switch(config-if)# service-policy output policy1
Switch(config-if)# end
Switch#
Switch# show policy-map policy1
Policy Map policy1
Class class1
shape average 256000
queue-limit 4048
Switch#
Active Queue Management by Using Dynamic Buffer Limiting
Active Queue Management (AQM) provides buffering control of traffic flows prior to queuing a packet
into a transmit queue of a port. In a shared-memory switch, this feature ensures that certain flows do not
retain the switch packet memory.
Note Catalyst 4900M, Catalyst 4948E, Supervisor Engine 6-E, and Supervisor Engine 6L-E support active
switch buffer management by using Dynamic Buffer Limiting (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 actions is configured.
To configure class-level DBL action along with shaping in a service policy, perform this task:
Command Purpose
Step 1
Switch# configure terminal
Enters global configuration mode.
Step 2
Switch(config)# policy-map
policy-map-name
Creates a policy map by entering the policy-map name, and enters
policy-map configuration mode.
By default, no policy maps are defined.
Step 3
Switch(config-pmap)# class class-name
Specifies the name of the class whose traffic policy you want to
create or change, and enters policy-map class configuration mode.
By default, no traffic classes are defined.
Step 4
Switch(config-pmap-class)# shape
average cir-bps
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.
Step 5
Switch(config-pmap-class)# dbl
Enables DBL on the queue associated with this class of traffic.
Step 6
Switch(config-pmap-class)# exit
Returns to policy-map configuration mode.