3750X QoS Problems

[DJX995]

I'm new to setting up QoS so I would like some input.

I'm setting up QoS on my 3750X:

Cisco IOS Software, C3750E Software (C3750E-UNIVERSALK9-M), Version 15.2(2)E, RELEASE SOFTWARE (fc3)

I enabled Auto QoS on the switch:

mls qos map policed-dscp  0 10 18 24 46 to 8
mls qos map cos-dscp 0 8 16 24 32 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 priority-queue 2 bandwidth 30
mls qos srr-queue input cos-map queue 1 threshold 2 3
mls qos srr-queue input cos-map queue 1 threshold 3 6 7
mls qos srr-queue input cos-map queue 2 threshold 1 4
mls qos srr-queue input dscp-map queue 1 threshold 2 24
mls qos srr-queue input dscp-map queue 1 threshold 3 48 49 50 51 52 53 54 55
mls qos srr-queue input dscp-map queue 1 threshold 3 56 57 58 59 60 61 62 63
mls qos srr-queue input dscp-map queue 2 threshold 3 32 33 40 41 42 43 44 45
mls qos srr-queue input dscp-map queue 2 threshold 3 46 47
mls qos srr-queue output cos-map queue 1 threshold 3 4 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 3 32 33 40 41 42 43 44 45
mls qos srr-queue output dscp-map queue 1 threshold 3 46 47
mls qos srr-queue output dscp-map queue 2 threshold 1 16 17 18 19 20 21 22 23
mls qos srr-queue output dscp-map queue 2 threshold 1 26 27 28 29 30 31 34 35
mls qos srr-queue output dscp-map queue 2 threshold 1 36 37 38 39
mls qos srr-queue output dscp-map queue 2 threshold 2 24
mls qos srr-queue output dscp-map queue 2 threshold 3 48 49 50 51 52 53 54 55
mls qos srr-queue output dscp-map queue 2 threshold 3 56 57 58 59 60 61 62 63
mls qos srr-queue output dscp-map queue 3 threshold 3 0 1 2 3 4 5 6 7
mls qos srr-queue output dscp-map queue 4 threshold 1 8 9 11 13 15
mls qos srr-queue output dscp-map queue 4 threshold 2 10 12 14
mls qos queue-set output 1 threshold 1 100 100 50 200
mls qos queue-set output 1 threshold 2 125 125 100 400
mls qos queue-set output 1 threshold 3 100 100 100 3200
mls qos queue-set output 1 threshold 4 60 150 50 200
mls qos queue-set output 1 buffers 15 25 40 20
mls qos

auto qos srnd4

All ports are setup like this:

interface GigabitEthernet1/0/1
 switchport mode access
 srr-queue bandwidth share 1 30 35 5
 priority-queue out
 mls qos trust dscp
 auto qos trust dscp

The problem is this:

I have an IPTV application that I tag with AF41 (DSCP 34):

policy-map QoS-Ceton-InfiniTV-Policy
 class QoS-Ceton-InfiniTV-Data-Class
  set dscp af41

But when I'm playing that application back on a client, packets are dropped when I'm also running Remote Desktop tagged with AF21 (DSCP 18).

Temporarily, I solved the problem by changing all ports to queue-set 2:
Queueset: 1
Queue     :       1       2       3       4
----------------------------------------------
buffers   :      15      25      40      20
threshold1:     100     125     100      60
threshold2:     100     125     100     150
reserved  :      50     100     100      50
maximum   :     200     400    3200     200
Queueset: 2
Queue     :       1       2       3       4
----------------------------------------------
buffers   :      25      25      25      25
threshold1:     100     200     100     100
threshold2:     100     200     100     100
reserved  :      50      50      50      50
maximum   :     400     400     400     400

What I don't get is Auto QoS is suppose to make this easy, isn't it?

How come AF41 packets are dropped for AF21 packets?

Thanks for any input.

[Jose Solano]

Hi,

Seems that the AF41 is mapped to queue 1 threshold 2 which on has 15% of the buffers while on queue-set 1. Since you moved the interfaces to queue set 2 and the issue was resolved is because queue-set 2 offers 25% buffers to queue 1, that said it may be a due to the buffers allocation that you are seeing drops since AF21 is also mapped to the same queue.

Hope this helps.

[DJX995]

show mls qos maps dscp-output-q
   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

Can you recommend how to change the configuration to better this situation?

Isn't priority-queue out suppose to address this issue?

This is 99.9% the way Auto-QoS set the switch up.

Only thing I changed was: mls qos queue-set output 1 threshold 3 100 100 100 3200, because I saw it on this forum.

Is setting the ports to queue-set 2 good enough?

Thanks!

[Jose Solano]

Hi,

Based on the output you attached AF41 is actually mapped to queue 1 threshold 3 and AF21 mapped to queue 2 threshold 1, so they should not interfere between each other. 

AF41 has 40% of the buffers while AF21 15%, now when you see the drops did you confirm on the mls qos interface xx statistics that the queue 1 threshold 3 drop counters were increasing?

Regards,

[DJX995]

Even with queue-set 2, I still see drops, just not as many.

GigabitEthernet1/0/27 (All statistics are in packets)

  dscp: incoming  
-------------------------------

  0 -  4 :     7324189            0            0            0            0  
  5 -  9 :           0            0            0            0            0  
 10 - 14 :           0            0            0            0            0  
 15 - 19 :           0            0            0       236744            0  
 20 - 24 :           0            0            0            0            0  
 25 - 29 :           0         1127            0            0            0  
 30 - 34 :           0            0            0            0            0  
 35 - 39 :           0            0            0            0            0  
 40 - 44 :           0            0            0            0            0  
 45 - 49 :           0            0            0            0            0  
 50 - 54 :           0            0            0            0            0  
 55 - 59 :           0            0            0            0            0  
 60 - 64 :           0            0            0            0  
  dscp: outgoing
-------------------------------

  0 -  4 :    17433393            2           94            0          163  
  5 -  9 :           0          291            0            1            0  
 10 - 14 :       30613            0            0            0            0  
 15 - 19 :           0         3822            0       281615            0  
 20 - 24 :           0            0            0            0       103072  
 25 - 29 :           0           11            0            0            0  
 30 - 34 :           0            0         7605            0     15387535  
 35 - 39 :           0            0            0            0            0  
 40 - 44 :           0            0            0            0            0  
 45 - 49 :           0            0            0        16394            0  
 50 - 54 :           0            0            0            0            0  
 55 - 59 :           0        18872            0            0            0  
 60 - 64 :           0            0            0            0  
  cos: incoming  
-------------------------------

  0 -  4 :     7564272            0            0            0            0  
  5 -  7 :           0            0            0  
  cos: outgoing
-------------------------------

  0 -  4 :    17467998        30614       285437       103083     15395140  
  5 -  7 :        7914        16394       209955  
  output queues enqueued:
 queue:    threshold1   threshold2   threshold3
-----------------------------------------------
 queue 0:           0           0        7605
 queue 1:    15673244      245425      264513
 queue 2:           0           0    17441610
 queue 3:           1       30602           0

  output queues dropped:
 queue:    threshold1   threshold2   threshold3
-----------------------------------------------
 queue 0:           0           0           0
 queue 1:           0           0           0
 queue 2:           0           0         588
 queue 3:           0           0           0

Policer: Inprofile:            0 OutofProfile:            0

[Jose Solano]

HI, 

I see that the drops happened on queue 3 threshold 3 which is only mapped for data traffic, not AF41 nor AF21. See below:

output queues dropped:
 queue:    threshold1   threshold2   threshold3
-----------------------------------------------
 queue 0:           0           0           0
 queue 1:           0           0           0
 queue 2:           0           0         588 <-----Drops queue 3 threshold 3
 queue 3:           0           0           0

Policer: Inprofile:            0 OutofProfile:            0

show mls qos maps dscp-output-q
   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 <-----Data traffic not AF41 nor AF21

[DJX995]

Interesting.

I will change back to queue-set 1 and recheck the counts.

I don't know whats wrong.

The IPTV application drops packets when I push a lot of data via RDP.