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Catalyst 2960 Switch SoftwareConfiguration Guide
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Chapter29 Co nfiguring QoS
Configuring Standard QoS
•On a port configured for QoS, all traffic received through the port is classified, pol iced, and marked
according to the policy map attached to the port. On a trunk port configured for QoS, traffic in all
VLANs received through the port is classified, policed, and marked according to the policy map
attached to the port.
•If you have EtherChannel ports configured on your switch, you must configure QoS classification,
policing, mapping, and queueing on the individual physical por ts that comprise the EtherChannel.
You must decide whether the QoS configuration should match on all ports in the EtherCh annel.

General QoS Guidelines

These are general QoS guidelines:
•Control traffic (such as spanning-tree bridge protocol data units [BPDUs] and routing update
packets) received by the switch are subject to all ingress QoS processing.
•You are likely to lose data when you change queue settings; therefore, try to make change s when
traffic is at a minimum.
Enabling QoS Globally
By default, QoS is disabled on the switch.
Beginning in privileged EXEC mode, follow these steps to enable QoS. This procedure is required.
To disable QoS, use the no mls qos global configuration command.
Configuring Classification Using Port Trust States
These sections describe how to classify incoming traffic by using port trust states. Depending on your
network configuration, you must perform one or more of these tasks or one or more of the tasks in the
“Configuring a QoS Policy” section on page 29-39:
•Configuring the Trust State on Ports within the QoS Domain, page 29-33
•Configuring the CoS Value for an Interface, page 29-34
•Configuring a Trusted Boundary to Ensure Port Security, page 29-35
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 mls qos Enable QoS globally.
QoS runs with the default settings described in the “Default
Standard QoS Configuration” section on page 29-29, the
“Queueing and Scheduling on Ingress Queues” section on
page 29-13, and the “Queueing and Scheduling on Egress
Queues” section on page 29-15.
Step3 end Return to privileged EXEC mode.
Step4 show mls qos Verify your entries.
Step5 copy running-config startup-config (Optional) Save your entries in the configuration file.