How to configure Queuing on Cisco 3560 and 3750 switch

Hi Joey,

Configuration-wise, WRR (Weighted Round Robin) and SRR (Shaped Round Robin) are very similar. You can use the examples in this lesson:

https://networklessons.com/quality-of-service/how-to-configure-queuing-on-cisco-catalyst-3560-and-3750-switch/

Something to keep in mind is that a lot of commands will only show up in your configuration if you use non-default values. Here’s an example:

Switch#show running-config | incl mls
mls qos

QoS has been enabled on this switch, that’s the only command we have in our config. Let’s check the default cos-dscp map:

Switch#show mls qos maps cos-dscp 
   Cos-dscp map:
        cos:   0  1  2  3  4  5  6  7 
     --------------------------------
       dscp:   0  8 16 24 32 40 48 56

If you try to add this to your config, it won’t show up. Here’s an experiment:

Switch(config)#mls qos map cos-dscp 0 8 16 24 32 40 48 56

Switch(config)#do sh run | incl qos
mls qos

It doesn’t show up since these are the default values. Only if we change something it will show up:

Switch(config)#mls qos map cos-dscp 0 8 16 24 32 40 48 60

Switch(config)#do sh run | incl qos                      
mls qos map cos-dscp 0 8 16 24 32 40 48 60
mls qos

Now you can see it in the config. There is another way though…if you use show running-config all then you will see everything, including the defaults:

Switch#show running-config all | incl mls
mls qos rewrite ip dscp
mls qos
 mls qos cos 0
 mls qos dscp-mutation Default DSCP Mutation Map

The mls qos cos 0 and mls qos dscp-mutation Default DSCP Mutation Map are found on the interfaces.

Rene