[c-nsp] Need help w/ output drops on 7613 WS-X6748-GE-TX

[Hank Nussbacher]

At 10:56 05/01/2011 +0100, Peter Rathlev wrote:

>Do you have QoS enabled? What does "show queueing interface Gi9/29" tell
>you?
>
>Output drops are "egress buffer overflow" drops, so technically it
>happens because the box tries to send a packet out an interface already
>in use (transmitting another packet) when there is no buffer space to
>store the packet until transmission. Micro-bursts and oversubscription
>are possible causes. Short queues exacerbate the problem. With "mls qos"
>enabled and no interface-specific adjustments you could have (too) short
>queues for the relevant traffic.

gp#show queueing interface Gi9/29
Interface GigabitEthernet9/29 queueing strategy:  Weighted Round-Robin
   Port QoS is enabled
   Port is untrusted
   Extend trust state: not trusted [COS = 0]
   Default COS is 0
     Queueing Mode In Tx direction: mode-cos
     Transmit queues [type = 1p3q8t]:
     Queue Id    Scheduling  Num of thresholds
     -----------------------------------------
        01         WRR                 08
        02         WRR                 08
        03         WRR                 08
        04         Priority            01

     WRR bandwidth ratios:  100[queue 1] 150[queue 2] 200[queue 3]
     queue-limit ratios:     50[queue 1]  20[queue 2]  15[queue 3]  15[Pri 
Queue]

     queue tail-drop-thresholds
     --------------------------
     1     70[1] 100[2] 100[3] 100[4] 100[5] 100[6] 100[7] 100[8]
     2     70[1] 100[2] 100[3] 100[4] 100[5] 100[6] 100[7] 100[8]
     3     100[1] 100[2] 100[3] 100[4] 100[5] 100[6] 100[7] 100[8]

     queue random-detect-min-thresholds
     ----------------------------------
       1    40[1] 70[2] 70[3] 70[4] 70[5] 70[6] 70[7] 70[8]
       2    40[1] 70[2] 70[3] 70[4] 70[5] 70[6] 70[7] 70[8]
       3    70[1] 70[2] 70[3] 70[4] 70[5] 70[6] 70[7] 70[8]

     queue random-detect-max-thresholds
     ----------------------------------
       1    70[1] 100[2] 100[3] 100[4] 100[5] 100[6] 100[7] 100[8]
       2    70[1] 100[2] 100[3] 100[4] 100[5] 100[6] 100[7] 100[8]
       3    100[1] 100[2] 100[3] 100[4] 100[5] 100[6] 100[7] 100[8]

     WRED disabled queues:

     queue thresh cos-map
     ---------------------------------------
     1     1      0
     1     2      1
     1     3
     1     4
     1     5
     1     6
     1     7
     1     8
     2     1      2
     2     2      3 4
     2     3
     2     4
     2     5
     2     6
     2     7
     2     8
     3     1      6 7
     3     2
     3     3
     3     4
     3     5
     3     6
     3     7
     3     8
     4     1      5

     Queueing Mode In Rx direction: mode-cos
     Receive queues [type = 2q8t]:
     Queue Id    Scheduling  Num of thresholds
     -----------------------------------------
        01         WRR                 08
        02         WRR                 08

     WRR bandwidth ratios:  100[queue 1]   0[queue 2]
     queue-limit ratios:    100[queue 1]   0[queue 2]

     queue tail-drop-thresholds
     --------------------------
     1     100[1] 100[2] 100[3] 100[4] 100[5] 100[6] 100[7] 100[8]
     2     100[1] 100[2] 100[3] 100[4] 100[5] 100[6] 100[7] 100[8]

     queue thresh cos-map
     ---------------------------------------
     1     1      0 1 2 3 4 5 6 7
     1     2
     1     3
     1     4
     1     5
     1     6
     1     7
     1     8
     2     1
     2     2
     2     3
     2     4
     2     5
     2     6
     2     7
     2     8


   Packets dropped on Transmit:

     queue     dropped  [cos-map]
     ---------------------------------------------
     1                  1590686  [0 1 ]
     2                      250  [2 3 4 ]
     3                        0  [6 7 ]
     4                        0  [5 ]

   Packets dropped on Receive:
     BPDU packets:  0

     queue              dropped  [cos-map]
     ---------------------------------------------
     1                        0  [0 1 2 3 4 5 6 7 ]
     2                        0  []

For mls:
sh conf | incl mls
mls ip multicast flow-stat-timer 9
mls ip multicast bidir gm-scan-interval 10
mls flow ip interface-full
no mls flow ipv6
mls nde sender version 5
mls qos statistics-export
mls qos
mls rate-limit multicast ipv4 ip-options 500 50
mls rate-limit all ttl-failure 100 10
no mls acl tcam share-global
mls cef error action freeze

How would you recommend adjusting the interface mls queues?

Thanks,
Hank