Cisco Catalyst 3560-X Series, Software Configuration Manual

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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
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Chapter 1 Configuring QoS
Configuring Standard QoS
Configuring SRR Shaped Weights on Egress Queues
You can specify how much of the available bandwidth is allocated to each queue. The ratio of the weights
is the ratio of frequency in which the SRR scheduler sends packets from each queue.
You can configure the egress queues for shaped or shared weights, or both. Use shaping to smooth bursty
traffic or to provide a smoother output over time. For information about shaped weights, see the
“SRR
Shaping and Sharing” section on page 1-15 . For information about shared weights, see the “Configuring
SRR Shared Weights on Egress Queues” section on page 1-89 .
Beginning in privileged EXEC mode, follow these steps to assign the shaped weights and to enable
bandwidth shaping on the four egress queues mapped to a port. This procedure is optional.
To return to the default setting, use the no srr-queue bandwidth shape interface configuration
command.
This example shows how to configure bandwidth shaping on queue 1. Because the weight ratios for
queues 2, 3, and 4 are set to 0, these queues operate in shared mode. The bandwidth weight for queue 1
is 1/8, which is 12.5 percent:
Switch(config)#
interface gigabitethernet2/0/1
Switch(config-if)# srr-queue bandwidth shape 8 0 0 0
Command Purpose
Step 1 configure terminal Enter global configuration mode.
Step 2 interface interface-id Specify the port of the outbound traffic, and enter interface configuration
mode.
Step 3
srr-queue bandwidth shape weight1
weight2 weight3 weight4
Assign SRR weights to the egress queues.
By default, weight1 is set to 25; weight2, weight3, and weight4 are set to 0,
and these queues are in shared mode.
For weight1 weight2 weight3 weight4 , enter the weights to control the
percentage of the port that is shaped. The inverse ratio (1/ weight ) controls
the shaping bandwidth for this queue. Separate each value with a space.
The range is 0 to 65535.
If you configure a weight of 0, the corresponding queue operates in shared
mode. The weight specified with the
srr-queue bandwidth shape
command is ignored, and the weights specified with the srr-queue
bandwidth share interface configuration command for a queue come into
effect. When configuring queues in the same queue-set for both shaping
and sharing, make sure that you configure the lowest number queue for
shaping.
The shaped mode overrides the shared mode.
Step 4 end Return to privileged EXEC mode.
Step 5 show mls qos interface interface-id
queueing
Verify your entries.
Step 6
copy running-config startup-config (Optional) Save your entries in the configuration file.