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Catalyst 2350 Switch Command Reference
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Chapter 2 Catalyst 2350 Switch Cisco IOS Commands
mls qos
mls qos
Use the
mls qos
global configuration command to enable quality of service (QoS) for the entire switch.
When the
mls qos
command is entered, QoS is enabled with the default parameters on all ports in the
system. Use the
no
form of this command to reset all the QoS-related statistics and to disable the QoS
features for the entire switch.
mls qos
no mls qos
Syntax Description
This command has no arguments or keywords.
Defaults
QoS is disabled. There is no concept of trusted or untrusted ports because the packets are not modified
(the CoS, DSCP, and IP precedence values in the packet are not changed). Traffic is switched in
pass-through mode (packets are switched without any rewrites and classified as best effort without any
policing).
When QoS is enabled with the
mls qos
global configuration command and all other QoS settings are set
to their defaults, traffic is classified as best effort (the DSCP and CoS value is set to 0) without any
policing. No policy maps are configured. The default port trust state on all ports is untrusted. The default
ingress and egress queue settings are in effect.
Command Modes
Global configuration
Command History
Usage Guidelines
QoS must be globally enabled to use QoS classification, policing, mark down or drop, queueing, and
traffic shaping features. You can create a policy-map and attach it to a port before entering the
mls qos
command. However, until you enter the
mls qos
command, QoS processing is disabled.
Policy-maps and class-maps used to configure QoS are not deleted from the configuration by the
no mls
qos
command, but entries corresponding to policy maps are removed from the switch hardware to save
system resources. To re-enable QoS with the previous configurations, use the
mls qos
command.
Toggling the QoS status of the switch with this command modifies (reallocates) the sizes of the queues.
During the queue size modification, the queue is temporarily shut down during the hardware
reconfiguration, and the switch drops newly arrived packets for this queue.
Examples
This example shows how to enable QoS on the switch:
Switch(config)#
mls qos
You can verify your settings by entering the
show mls qos
privileged EXEC command.
Release
Modification
12.2(46)EY
This command was introduced.