Too large frames/Outdiscards errors

Question

Hi !
We have a problem with switch connected to an IBM Chassis (model : WS-CBS3012-IBM-I).
Several links seem to flap from time to time and we have dropped packets (Outdiscards) :
XXX#show interfaces counters errors
Port        Align-Err     FCS-Err    Xmit-Err     Rcv-Err  UnderSize  OutDiscards
Gi0/7               0           0           0           0          0        43983
XXX#show controllers ethernet-controller gigabitEthernet 0/7
     Transmit GigabitEthernet0/7              Receive
   2584788113 Bytes                        971769475 Bytes
   2128747524 Unicast frames              2142250737 Unicast frames
     10109338 Multicast frames                  7644 Multicast frames
     11694673 Broadcast frames                  1660 Broadcast frames
            0 Too old frames               991831483 Unicast bytes
            0 Deferred frames                 726180 Multicast bytes
            0 MTU exceeded frames             106240 Broadcast bytes
            0 1 collision frames                   0 Alignment errors
            0 2 collision frames                   0 FCS errors
            0 3 collision frames                   0 Oversize frames
            0 4 collision frames                   0 Undersize frames
            0 5 collision frames                   0 Collision fragments
            0 6 collision frames
            0 7 collision frames                   0 Minimum size frames
            0 8 collision frames           208582465 65 to 127 byte frames
            0 9 collision frames           286273443 128 to 255 byte frames
            0 10 collision frames           15408397 256 to 511 byte frames
            0 11 collision frames           12313490 512 to 1023 byte frames
            0 12 collision frames           10599137 1024 to 1518 byte frames
            0 13 collision frames                  0 Overrun frames
            0 14 collision frames                  0 Pause frames
            0 15 collision frames
            0 Excessive collisions                 0 Symbol error frames
            0 Late collisions                      0 Invalid frames, too large
            0 VLAN discard frames         1609083109 Valid frames, too large
            0 Excess defer frames                  0 Invalid frames, too small
       320523 64 byte frames                       0 Valid frames, too small
    396763728 127 byte frames
      6601722 255 byte frames                      0 Too old frames
     28139208 511 byte frames                      0 Valid oversize frames
      4064656 1023 byte frames                     0 System FCS error frames
    285633065 1518 byte frames                     0 RxPortFifoFull drop frame
   1429028633 Too large frames
            0 Good (1 coll) frames
            0 Good (>1 coll) frames
The interface is Full-1000 and is configured :
interface GigabitEthernet0/7
 description "SRV-001-PRD-VM1 - VMNic0"
 switchport trunk allowed vlan 11,12,99
 switchport mode trunk
 link state group 1 downstream
end
For the "too large frames", I have already read the post : https://supportforums.cisco.com/discussion/11034901/too-large-frames-what-does-mean-performance, so, I think it's not serious.
But I don't know why some packets are dropped because the configuration seems good ...
Can you help me please ?
Thank you in advance !

Answer 1

87752686 Valid frames, too large
This is nothing.  You get this counters if the port(s) is/are configured as Dot1Q Trunking.  
There is nothing to be worried about.