output drops on interface don't match drops in class based queues

[rejackson]

Like the heading says, the interface is dropping output but the queues dont show as many drops.  Are the class based queues nested inside one overall queue for the interface?

Houston#sh queueing inter s 1/0
Interface Serial1/0 queueing strategy: fair
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 3423
  Queueing strategy: Class-based queueing
  Output queue: 21/1000/64/3423 (size/max total/threshold/drops)
     Conversations  4/64/256 (active/max active/max total)
     Reserved Conversations 3/3 (allocated/max allocated)
     Available Bandwidth 2 kilobits/sec

  (depth/weight/total drops/no-buffer drops/interleaves) 13/32/905/0/0
  Conversation 266, linktype: ip, length: 1304
  source: 10.1.2.105, destination: 24.143.192.67, id: 0x159C, ttl: 127,
  TOS: 64 prot: 6, source port 1686, destination port 80

  (depth/weight/total drops/no-buffer drops/interleaves) 2/32384/0/0/0
  Conversation 6, linktype: ip, length: 44
  source: 10.1.2.3, destination: 10.1.214.12, id: 0x70A0, ttl: 255,
  TOS: 0 prot: 6, source port 22, destination port 1512

  (depth/weight/total drops/no-buffer drops/interleaves) 1/32384/5/0/0
  Conversation 198, linktype: ip, length: 148
  source: 10.1.2.7, destination: 10.1.213.51, id: 0xD7F0, ttl: 127,
  TOS: 0 prot: 6, source port 445, destination port 1749

  (depth/weight/total drops/no-buffer drops/interleaves) 5/32384/60/0/0
  Conversation 94, linktype: ip, length: 1504
  source: 10.1.2.133, destination: 10.1.1.227, id: 0xEE85, ttl: 127,
  TOS: 0 prot: 6, source port 1810, destination port 445

[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

You're comparing active flow queue drops against all cumulative drops.  They're unlikely to match.

[rejackson]

I guess I should have pasted in the show policy map displays that I was talking about. Now this page won't let me paste anything. But the show policy map shows about 1200 packets dropped between all the queues.  The interface show 14000 packets dropped.

[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

I vaguely recall that interface counts drops for any cause, class drops might only account for queue drops in that class.  What might cause them to differ?  Perhaps no-buffer drops, but again, this is only a vague recollection.