QoS DSCP to Output Queues

[PolyCaleb]

I'm using a 3560X-24P running 12.2(55)SE5 IPBase.

I should be getting a lot more packets queued into my queue 2 than I am and I'm not sure why I'm not.  Any help would be appreciated as it makes it very hard to properly allocate buffers if the packets don't go where you expect them to.

All statistics are from the same port:

  output queues enqueued:
 queue:    threshold1   threshold2   threshold3
-----------------------------------------------
 queue 0:           0           0           0
 queue 1:        1707       30712       43244
 queue 2:           0           0        1257
 queue 3:           0           0           0

  dscp: outgoing
-------------------------------

  0 -  4 :       31968            0            0            0            0
  5 -  9 :           0            0            0            0            0
 10 - 14 :           0            0            0            0            0
 15 - 19 :           0            0            0          630            0
 20 - 24 :           0            0            0            0            0
 25 - 29 :           0            8            0            0            0
 30 - 34 :           0            0            0            0         1069
 35 - 39 :           0            0            0            0            0
 40 - 44 :           0            0            0            0            0
 45 - 49 :           0            0            0        32463            0
 50 - 54 :           0            0            0            0            0
 55 - 59 :           0            0            0            0            0
 60 - 64 :           0            0            0            0

  cos: outgoing
-------------------------------

  0 -  4 :       31969            0          630            8         1069
  5 -  7 :           0        32473        10771

GigabitEthernet0/24
trust state: trust dscp
trust mode: trust dscp
trust enabled flag: ena
COS override: dis
default COS: 0
DSCP Mutation Map: Default DSCP Mutation Map
Trust device: none
qos mode: port-based

These are global settings:

  Dscp-outputq-threshold map:
     d1 :d2    0     1     2     3     4     5     6     7     8     9
     ------------------------------------------------------------
      0 :    03-03 03-03 03-03 03-03 03-03 03-03 03-03 03-03 04-01 04-01
      1 :    04-02 04-01 04-02 04-01 04-02 04-01 02-01 02-01 02-01 02-01
      2 :    02-01 02-01 02-01 02-01 02-02 03-01 02-01 02-01 02-01 02-01
      3 :    02-01 02-01 01-03 01-03 02-01 02-01 02-01 02-01 02-01 02-01
      4 :    01-03 01-03 01-03 01-03 01-03 01-03 01-03 01-03 02-03 02-03
      5 :    02-03 02-03 02-03 02-03 02-03 02-03 02-03 02-03 02-03 02-03
      6 :    02-03 02-03 02-03 02-03

  Cos-outputq-threshold map:
              cos:  0   1   2   3   4   5   6   7
              ------------------------------------
  queue-threshold: 3-3 4-3 2-1 2-2 1-3 1-3 2-3 2-3

[Joseph W. Doherty]

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Posting

Per chance, you're not being mislead by how the 3750 sometimes starts counting its egress queues with number zero and sometimes with number 1?  I.e. your 2nd egress queue might be numbered 1 or 2, depending on statistic reference.

[PolyCaleb]

Thanks for the response but I was aware of the differencing in how they are numbered.  However does having the priority out queue turned on further shift the number?

Since:

My DSCP to Queue-Threshold mapping states that DSCP 0 is sent to the 3rd Queue 3rd Threshold (DSCP-Output Queues uses 1 through 4).

From my DSCP outgoing I have 31968 packets with DSCP 0.

Since my output queue enqueued stats go from Queue 0 to Queue 3, I would expect the 31968 packets to be in my Queue 2 3rd Threshold.  However my queue 2 3rd threshold only has 1257 packets.  What happened to the other 30000 packets?

[Joseph W. Doherty]

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

Good that you understand as I wasn't sure which Q2 you were referencing.

As far as I know, enabling interface PQ does not shift egress queue numbering.

Yes, I see DSCP 0 is directed to queue 3, WTD 3.

Looking more carefully at your OP stats, you might be looking at some form of bug.  Notice the total number of enqueued packets is about the same as COS outgoing, but DSCP outgoing is about 10K short.

Try upgrading to 55SE9 and see what your stats look like.