MLS QoS configuration

[Eric Rickard]

Good Morning, everyone.  I am looking for some clarification with an existing 3750x Switch configuration.  

I am reviewing the configuration of my network switches and found the following MLS QoS configuration on one of my switches and a partial of this same config on another switch.  Can someone please explain what function, this line of code, is performing; and is it necessary?

mls qos map policed-dscp  0 14 24 30 38 to 8
mls qos map policed-dscp  10 to 12
mls qos map policed-dscp  12 to 14
mls qos map policed-dscp  26 to 28
mls qos map policed-dscp  28 to 30
mls qos map policed-dscp  32 to 34
mls qos map policed-dscp  34 to 36
mls qos map policed-dscp  36 to 38
mls qos map cos-dscp 0 8 16 24 34 46 48 56
mls qos srr-queue input bandwidth 70 30
mls qos srr-queue input threshold 1 80 90
mls qos srr-queue input threshold 2 80 90
mls qos srr-queue input priority-queue 2 bandwidth 30
mls qos srr-queue input dscp-map queue 1 threshold 2 16 24
mls qos srr-queue input dscp-map queue 1 threshold 3 48 56
mls qos srr-queue input dscp-map queue 2 threshold 1 36 38
mls qos srr-queue input dscp-map queue 2 threshold 2 32 34
mls qos srr-queue input dscp-map queue 2 threshold 3 40 46
mls qos srr-queue output cos-map queue 1 threshold 2 4
mls qos srr-queue output cos-map queue 1 threshold 3 5
mls qos srr-queue output cos-map queue 2 threshold 1 2
mls qos srr-queue output cos-map queue 2 threshold 2 3
mls qos srr-queue output cos-map queue 2 threshold 3 6 7
mls qos srr-queue output cos-map queue 3 threshold 3 0
mls qos srr-queue output cos-map queue 4 threshold 3 1
mls qos srr-queue output dscp-map queue 1 threshold 2 32 34
mls qos srr-queue output dscp-map queue 1 threshold 3 40 46
mls qos srr-queue output dscp-map queue 2 threshold 1 18 20 22 26 28 30
mls qos srr-queue output dscp-map queue 2 threshold 2 16 24
mls qos srr-queue output dscp-map queue 2 threshold 3 48 56
mls qos srr-queue output dscp-map queue 3 threshold 3 0
mls qos srr-queue output dscp-map queue 4 threshold 1 8
mls qos srr-queue output dscp-map queue 4 threshold 2 12 14
mls qos srr-queue output dscp-map queue 4 threshold 3 10
mls qos queue-set output 1 threshold 1 100 100 100 100
mls qos queue-set output 1 threshold 2 80 90 100 400
mls qos queue-set output 1 threshold 3 100 100 100 400
mls qos queue-set output 1 threshold 4 90 100 100 400
mls qos queue-set output 1 buffers 15 30 35 20
mls qos

If more information is required for a response, please let me know.

Thank you, E.

[Joseph W. Doherty]

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Posting

The function of each command is perhaps best explained by the Command Reference and Software Configuration Guide for your IOS version.  If you have a question that's unanswered by those, please post another question.  BTW, Cisco also publishes whitepapers that further explain some subjects.  There are a couple on 3750 QoS.

Regarding whether a particular command is necessary would depend on what your QoS policy is attempting to accomplish.