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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
Sharing (Bandwidth)
The bandwidth assigned to a class of traffic is the minimum bandwidth that is guaranteed to the class
during congestion. Transmit queue sharing is the process by which output link bandwidth is shared
among multiple queues of a given port.
Catalyst 4900M, Catalyst 4948E, Supervisor Engine 6-E, and Supervisor Engine 6L-E support a range
of 32 kbps to 10 Gbps for sharing, with a precision of approximately +/- 0.75 percent. The sum of
configured bandwidth across all queuing classes should not exceed the link bandwidth.
To configure class-level bandwidth action 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 enter policy-map class configuration mode.
By default, no traffic classes are defined.
Step 4
Switch(config-pmap-class)# bandwidth
{bandwidth-kbps | percent percent}
Specifies the minimum bandwidth provided to a class belonging to
the policy map when there is traffic congestion in the switch. If the
switch is not congested, the class receives more bandwidth than you
specify with the bandwidth command.
By default, no bandwidth is specified.
You can specify the bandwidth in kbps or as a percentage:
• For bandwidth-kbps, specify the bandwidth amount in kbps
assigned to the class. The range is 32 to 10000000.
• For percent, specify the percentage of available bandwidth
assigned to the class. The range is 1 to 100.
Specify all the class bandwidths in either kbps or in percentages, but
not a mix of both.
Step 5
Switch(config-pmap-class)# exit
Returns to policy-map configuration mode.
Step 6
Switch(config-pmap)# exit
Returns to global configuration mode.
Step 7
Switch(config)# interface interface-id
Specifies a physical port and enters interface configuration mode.
Step 8
Switch(config-interface)#
service-policy output policy-map-name
Specifies the policy-map name, and applies it a physical interface.
Step 9
Switch(config-interface)# end
Returns to privileged EXEC mode.
Step 10
Switch# show policy-map
[policy-map-name [class
class-map-name]]
or
Switch# show policy-map interface
interface-id
Verifies your entries.
Step 11
Switch# copy running-config
startup-config
(Optional) Saves your entries in the configuration file.
