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3750 QoS: Output dscp-map Queue numbering mis-match?

desmith
Level 1
Level 1

Hello, all.

When configuring QoS on 3750s/3560s, we're mapping packets to particular interface output queues with commands such as:

       mls qos srr-queue output dscp-map queue 1 threshold 2 32

The queue numbers available for use in this command are 1-4, i.e.,

       mls qos srr-queue output dscp-map queue 1 threshold <etc.>

       mls qos srr-queue output dscp-map queue 2 threshold <etc.>

       mls qos srr-queue output dscp-map queue 3 threshold <etc.>

       mls qos srr-queue output dscp-map queue 4 threshold <etc.>

The command to see what's actually being enqueued, dropped, etc. is:

       show mls qos interface < > statistics

The end of the output of this command shows:

  output queues enqueued:

queue:    threshold1   threshold2   threshold3

-----------------------------------------------

queue 0:          11           0           0

queue 1:     7322430    17421520    22046162

queue 2:           0           0    81775734

queue 3:       23048           0     7294764

  output queues dropped:

queue:    threshold1   threshold2   threshold3

-----------------------------------------------

queue 0:           0           0           0

queue 1:         935       45106           0

queue 2:           0           0      185537

queue 3:           2           0           0

Note that these queues are numbered 0 - 3, and not 1 - 4.  We've been assuming that the first queue number in the "mls qos" (i.e., 1) command maps to the first queue (i.e., 0) in the "show mls qos" command.

We're wondering if anyone can confirm this from certain knowledge, or if perhaps we're missing something.

Thanks much for any help you can give!

Deb

1 Reply 1

Mike Pavlovich
Cisco Employee
Cisco Employee

You are correct, queue 0-3 corresponds to queue 1-4.

You can also take a look at the following post which gives some additional commands and 3750 QoS theory....

https://supportforums.cisco.com/message/3154960#3154960

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