[c-nsp] 3548XL high amount of input overruns

[Brad Beck]

Hi Group,

I've got several 3548XL switches running 12.0(5)WC17, which is the latest IOS available, and I'm hoping that someone may have a word of wisdom to share concerning this problem.

I'm seeing a high number of Overruns on the input side of my gigabit uplink (gig0/1).  Upstream from this switch is a 3560-12SD.  The port is configured as dot1q.

Both sides are configured as follows:
interface GigabitEthernet0/1
 load-interval 30
 no flowcontrol
 switchport trunk encapsulation dot1q
 switchport mode trunk

The general topology goes like this:

3560_g0/7---g0/1_3548XL_g0/2--g0/1_3548XLg0/2--(two other 3548XLs connected identically).

The odd thing is that I'm seeing these overruns on the g0/1 interface on the other downstream 3548s in this topology.  From the output below, it looks like these overruns are mapped to ignored packets in the "show int" counter.   It doesn't look to me as though these interfaces are saturated.

CSAMS20E#sh controllers ethernet-controller g0/1

  Transmit                           Receive
 838304857 Bytes                  1766197372 Bytes
   2860115 Unicast frames           10943597 Unicast frames
      8236 Multicast frames          1535829 Multicast frames
     58983 Broadcast frames          1046491 Broadcast frames
         2 Discarded frames                0 No bandwidth frames
         0 Too old frames                  0 No buffers frames
         0 Deferred frames            662410 No dest, unicast
         0  1 collision frames           248 No dest, multicast
         0  2 collision frames           522 No dest, broadcast
         0  3 collision frames             0 Alignment errors
         0  4 collision frames             0 FCS errors
         0  5 collision frames             4 Collision fragments
         0  6 collision frames
         0  7 collision frames             0 Undersize frames
         0  8 collision frames       1593073 Minimum size frames
         0  9 collision frames       2535548 65 to 127 byte frames
         0 10 collision frames       4441434 128 to 255 byte frames
         0 11 collision frames       2726228 256 to 511 byte frames
         0 12 collision frames        167124 512 to 1023 byte frames
         0 13 collision frames       2764216 1024 to 1518 byte frames
         0 14 collision frames             0 Oversize frames
         0 15 collision frames       7811787 Flooded frames
         0 Excessive collisions        38522 Overrun frames
         0 Late collisions                 0 VLAN filtered frames
         0 Good (1 coll) frames            0 Source routed frames
         0 Good(>1 coll) frames            0 Valid oversize frames
         0 Pause frames                    0 Pause frames
         0 VLAN discard frames             0 Symbol error frames
         0 Excess defer frames             0 Invalid frames, too large
         0 Too large frames                0 Valid frames, too large
   1193690 64 byte frames                  0 Invalid frames, too small
    551884 127 byte frames                 0 Valid frames, too small
    523161 255 byte frames             29407  0 Addr Cmp frames
    265725 511 byte frames           4743187  1 Addr Cmp frames
     72053 1023 byte frames          8217774  2 Addr Cmp frames
    320821 1518 byte frames          1148797  3 Addr Cmp frames
                                       49936  4 Addr Cmp frames
                                           0  5 Addr Cmp frames
                                           0  6 Addr Cmp frames
                                           0  7 Addr Cmp frames
                                           0  8 Addr Cmp frames
                                           0  9 Addr Cmp frames
                                           0 10 Addr Cmp frames
                                           0 11 Addr Cmp frames
                                           0 12 Addr Cmp frames
                                           0 13 Addr Cmp frames
                                           0 14 Addr Cmp frames
                                           0 15 Addr Cmp frames

GigabitEthernet0/1 is up, line protocol is up
  Hardware is Gigabit Ethernet, address is 0030.85f7.a131 (bia 0030.85f7.a131)
  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive not set
  Auto-duplex (Full), 1000Mb/s, media type is SX
  output flow-control is off, input flow-control is off
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:00, output 00:00:22, output hang never
  Last clearing of "show interface" counters never
  Queueing strategy: fifo
  Output queue 0/40, 0 drops; input queue 0/75, 0 drops
  30 second input rate 2711000 bits/sec, 614 packets/sec
  30 second output rate 880000 bits/sec, 380 packets/sec
     14480857 packets input, 1949661670 bytes, 0 no buffer
     Received 2604918 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 38522 ignored
     0 watchdog, 1548965 multicast, 0 pause input
     3097851 packets output, 880079599 bytes, 2 underruns
     0 output errors, 0 collisions, 2 interface resets
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier, 0 pause output
     2 output buffer failures, 0 output buffers swapped out

It doesn't look like saturation to me, average rate over five minutes is under 40Mb peak.

Any ideas?  Thanks much!



Note: The information contained in this message may be privileged and confidential and protected from disclosure. If the reader of this message is not the intended recipient, or an employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that any dissemination, distribution or copying of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by replying to the message and deleting it from your computer.