Command:

mls qos cos


Mode:

Switch(config-if)#


Syntax:

mls qos cos {default-cos | override}
no mls qos cos {default-cos | override}

 

Syntax Description:

default-cos Assign a default CoS value to a port. If the port is CoS trusted and packets are untagged, the default CoS value becomes a CoS value used to select one output queue to index into the CoS-to-Differentiated Services Code Point (DSCP) map. The CoS range is 0 to 7.
override Override the CoS of the incoming packets, and apply the default CoS value on the port to all incoming packets.

 

Command Description:

Use the mls qos cos interface configuration command to define the default class of service (CoS) value of a port or to assign the default CoS to all incoming packets on the port. Use the no form of this command to return to the default setting.

The default CoS value for a port is 0.

CoS override is disabled by default.

You can use the default value to assign CoS and DSCP values to all packets entering a port if the port has been configured by using the override keyword.

Use the override keyword when all incoming packets on certain ports deserve higher or lower priority than packets entering from other ports. Even if a port was previously set to trust DSCP or CoS, this command overrides that trust state, and all the incoming CoS values are assigned the default CoS value configured with the mls qos cos command. If an incoming packet is tagged, the CoS value of the packet is modified with the default CoS of the port at the ingress port.


Example:

This example shows how to configure the default port CoS to 4:

Switch(config)#interface gigabitethernet 0/1
Switch(config-if)#mls qos trust cos
Switch(config-if)#mls qos cos 4

This example shows how to assign all the packets entering a port to the default port CoS value of 4:

Switch(config)#interface gigabitethernet 0/1
Switch(config-if)#mls qos cos 4
Switch(config-if)#mls qos cos override
 


You can verify your settings by entering the show mls qos interface privileged EXEC command.


Misconceptions:

None


Related Commands:

mls qos map
mls qos trust

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