Cisco Catalyst 3750-X User Manual

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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-21521-01
Chapter 39 Configuring QoS
Configuring Standard QoS
Beginning in privileged EXEC mode, follow these steps to enable the egress expedite queue. This
procedure is optional.
To disable the egress expedite queue, use the no priori
ty-queue out interface configuration command.
This example shows how to enable the e
gress expedite queue when the SRR weights are configured. The
egress expedite queue overrides the configured SRR weights.
Switch(config)# interface gigabitethernet1/0/1
Switch(config-if)# srr-queue band
width shape 25 0 0 0
Switch(config-if)# srr-queue band
width share 30 20 25 25
Switch(config-if)# priority-queue
out
Switch(config-if)# end
Limiting the Bandwidth on an Egress Interface
You can limit the bandwidth on an egress port. For example, if a customer pays only for a small
percentage of a high-speed link, you can limit the bandwidth to that amount.
Note The egress queue default settings are suitable for most situations. You should change them only when
you have a thorough understanding of the egress queues and if these settings do not meet your QoS
solution.
Beginning in privileged EXEC mode, follow these steps to limit the bandwidth on an egress port. This
procedure is optional.
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
mls qos Enable QoS on a switch.
Step 3
interface interface-id Specify the egress port, and enter interface configuration mode.
Step 4
priority-queue out Enable the egress expedite queue, which is disabled by default.
When you configure this command, the SRR weight and queue size ratios
ar
e affected because there is one fewer queue participating in SRR. This
means that weight1 in the srr-queue bandwidth shape or the srr-queue
bandwidth share command is ignored (not used in the ratio calculation).
Step 5
end Return to privileged EXEC mode.
Step 6
show running-config Verify your entries.
Step 7
copy running-config startup-config (Optional) Save your entries in the configuration file.
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
interface interface-id Specify the port to be rate limited, and enter interface configuration mode.
Step 3
srr-queue bandwidth limit weight1 Specify the percentage of the port speed to which the port should be
limited. The range is 10 to 90.
By default, the port is not rate limited and is set to 100 percent.
Step 4
end Return to privileged EXEC mode.

Cisco Catalyst 3750-X Specifications

General

Switching Capacity	160 Gbps
Stacking Bandwidth	64 Gbps
Max Stacking Units	9
Layer Support	Layer 2 and Layer 3
Form Factor	Rack-mountable
DRAM	256 MB
Flash Memory	64 MB
Model	Cisco Catalyst 3750-X Series
Ports	24 or 48 10/100/1000 Ethernet ports
Uplink Interfaces	4 SFP or 2 SFP+
Features	StackWise Plus, EnergyWise
Image	IP Base or IP Services
Operating Temperature	0 to 40°C
Operating Humidity	10 to 85% noncondensing