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Constantly increasing "UnderSize" packets shown in "show interface counters errors" output

Hi experts,

I see increasing "UnderSize" packets on my WS-C3560G-24TS switch with IOS 12.2(25)SEE3. I have checked the duplex and speed settings and both ends are set to full/100mbps.

sw01#sh interface counters errors

Port        Align-Err    FCS-Err   Xmit-Err    Rcv-Err UnderSize

Gi0/1               0          0          0          01775172073

What does this error indicate? When I do "show interface g0/1" I dont see any runts though...

sw01#sh int g0/1

GigabitEthernet0/1 is up, line protocol is up (connected)

  Hardware is Gigabit Ethernet, address is 0016.c829.5401 (bia 0016.c829.5401)

  Description: uplink to 2851 g0/0

  MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,

     reliability 255/255, txload 5/255, rxload 8/255

  Encapsulation ARPA, loopback not set

  Keepalive set (10 sec)

  Full-duplex, 100Mb/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 00:00:47, output 00:00:00, output hang never

  Last clearing of "show interface" counters never

  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

  Queueing strategy: fifo

  Output queue: 0/40 (size/max)

  5 minute input rate 3294000 bits/sec, 484 packets/sec

  5 minute output rate 2223000 bits/sec, 670 packets/sec

     3149141350 packets input, 1493671892 bytes, 0 no buffer

     Received 3596166 broadcasts (0 multicast)

     0 runts, 0 giants, 0 throttles

     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

     0 watchdog, 470314 multicast, 46 pause input

     0 input packets with dribble condition detected

     1504325738 packets output, 3605884235 bytes, 0 underruns

     0 output errors, 0 collisions, 1 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

Any ideas? Thanks!

Cisco Employee

Constantly increasing "UnderSize" packets shown in "show interfa

Hello Difan,

I believe I have been discussing a somewhat similar issue in the following thread:

Do you believe that the topic of that thread would be relevant also here?

Best regards,


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