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New Member

I can not disable QOS on the interface of Catalyst 3750 switch, and I still see output drops on the interface

I tried to disable QOS function to a port of switch 3750 by following commands, then tried to clear its counter

(config)#int g3/0/24

                    no mls qos

#clear mls qos interface g3/0/24 statistics

#clear counters g3/0/24

 

But it doesn't work , I still see some "output drops" on the interface;  

I execute "show mls qos int g3/0/24 statistics " command, there are still 11 output drops in queue3 threshold3.(see below)

 

#sh mls qos int g3/0/24 statistics 
GigabitEthernet3/0/24 (All statistics are in packets)

 

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

  0 -  4 :       12913          0         7642         0            0  
  5 -  9 :             0            0            0            0            0  
 10 - 14 :           0            0            0            0            0  
 15 - 19 :           0            0            0         4527         0  
 20 - 24 :           0            0            0            0            0  
 25 - 29 :           0            4            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            3            0         1561         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 :       40073          0            0            0            0  
  5 -  9 :             0            0            0            0            0  
 10 - 14 :           0            0            0            0            0  
 15 - 19 :           0            0            0            0            0  
 20 - 24 :           0            0            0            0            0  
 25 - 29 :           0            0            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          302          0  
 50 - 54 :           0            0            0            0            0  
 55 - 59 :           0            0            0            0            0  
 60 - 64 :           0            0            0            0  
 

cos: incoming  
-------------------------------

  0 -  4 :       26887        0            0            0            0  
  5 -  7 :           0            0            0  
  cos: outgoing 
-------------------------------

  0 -  4 :       44093        0            0            0            0  
  5 -  7 :           0          302          503  
 

output queues enqueued: 
 queue:    threshold1   threshold2   threshold3
-----------------------------------------------
 queue 0:           0           0           0 
 queue 1:        4651        0         503 
 queue 2:           0           0           0 
 queue 3:           0           0       39744 

 

output queues dropped: 
 queue:    threshold1   threshold2   threshold3
-----------------------------------------------
 queue 0:           0           0           0 
 queue 1:           0           0           0 
 queue 2:           0           0           0 
 queue 3:           0           0          11   ---> dorps!

Policer: Inprofile:            0 OutofProfile:            0 

 

By command of "show interface g3/0/24" , I also see 11 output drops , and the output data is 57827903 bytes =55.14899 Megabytes during the time

 

LRC199SW203#sh int g3/0/24
GigabitEthernet3/0/24 is up, line protocol is up (connected) 
  Hardware is Gigabit Ethernet, address is b0fa.eb62.8f98 (bia b0fa.eb62.8f98)
  Description: 168 xxxx Ave fl 3  AP3602E-160LRC3D
  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec, 
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full-duplex, 1000Mb/s, media type is 10/100/1000BaseTX
  input flow-control is off, output flow-control is unsupported 
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:06, output 00:00:50, output hang never
  Last clearing of "show interface" counters 00:37:59
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 11  ---> drops!
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 44000 bits/sec, 14 packets/sec
  5 minute output rate 193000 bits/sec, 52 packets/sec
     78282 packets input, 36263371 bytes, 0 no buffer
     Received 158 broadcasts (120 multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 120 multicast, 0 pause input
     0 input packets with dribble condition detected
     121867 packets output, 57827903 bytes, 0 underruns
     0 output errors, 0 collisions, 0 interface resets
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier, 0 PAUSE output
     0 output buffer failures, 0 output buffers swapped out

 

 

To make sure I already disabled  QOS on the interface, I type following show commands to verify

 

"sh mls qos int g3/0/24"

   GigabitEthernet3/0/24
   QoS is disabled. When QoS is enabled, following settings will be applied
   trust state: trust cos
   trust mode: trust cos
   trust enabled flag: ena
   COS override: dis
   default COS: 0
   DSCP Mutation Map: Default DSCP Mutation Map
   Trust device: none
   qos mode: port-based

 

 

"sh mls qos int g3/0/24 policers" 

   GigabitEthernet3/0/24
   QoS is disabled. When QoS is enabled, following settings will be applied

 

 

 

 

 

  • LAN Switching and Routing
5 REPLIES
New Member

the original port

the original port configuration is :

 

interface GigabitEthernet3/0/24
   description 168 xxxxx fl 3  AP3602E-160LRC3D
   switchport access vlan 610
   switchport mode access
   srr-queue bandwidth share 1 30 35 5
   priority-queue out 
   mls qos trust cos
   auto qos trust 
   spanning-tree bpduguard enable
   ip dhcp snooping trust 

Cisco Employee

Hi, If you dont want qos

Hi,

 

If you dont want qos action on this interface, can you try to remove below commands from the interface.

 

interface GigabitEthernet3/0/24
   description 168 xxxxx fl 3  AP3602E-160LRC3D
   switchport access vlan 610
   switchport mode access
   srr-queue bandwidth share 1 30 35 5 <<<<<<<<<<<
   priority-queue out   <<<<<<<<<<<<<<
   mls qos trust cos   <<<<<<<<<<<<<
   auto qos trust         <<<<<<<<<<<<<<
   spanning-tree bpduguard enable
   ip dhcp snooping trust 

 

Regards,

Akash

Super Bronze

DisclaimerThe Author of this

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

My experience on 3750 has been generally only a reload will clear the detailed MLS QoS stats.

However, I thought could could clear the interface stats, although, if not, might be a bug in your IOS version (you didn't note actual 3750 model or specific IOS version being used).

Lastly, the interface stats don't clear at all?  Reason I ask, disabling QoS doesn't preclude you still getting drops.

New Member

I did disable QOS funcation

I did disable QOS funcation and removed all QOS related commands in the interface, then reloaded the switch ,  but still see outputs drops.

 

 

Super Bronze

DisclaimerThe Author of this

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

Disabling QoS doesn't not eliminate the possibility of output drops, and they will still be counted.  However, did all the counters reset with the reload, and do the drops now all only accumulate in one counter?

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