Input errors trunk interface catalyst 4500

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Nov 25th, 2008
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Hi to all!

I'm having alot of input errors in a Gigabit interface of a catalyst 4500, it is configured as trunk an connected to a catalyst 2960G, in the interface of the 2960G are not any input errors just in the 4500, we already replace the cable between the devices but the situation remains.

CORE1#sh int gi7/45

GigabitEthernet7/45 is up, line protocol is up (connected)

  Hardware is Gigabit Ethernet Port, address is 001b.d403.ffcc (bia 001b.d403.ffcc)

  Description: Trunk SERVERS2-2 0/47

  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,

     reliability 255/255, txload 14/255, rxload 2/255

  Encapsulation ARPA, loopback not set

  Keepalive set (10 sec)

  Full-duplex, 1000Mb/s, link type is auto, media type is 10/100/1000-TX

  input flow-control is off, output flow-control is off

  ARP type: ARPA, ARP Timeout 04:00:00

  Last input 00:00:16, output never, output hang never

  Last clearing of "show interface" counters 4d16h

  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0

  Queueing strategy: fifo

  Output queue: 0/40 (size/max)

  5 minute input rate 10877000 bits/sec, 2163 packets/sec

  5 minute output rate 56541000 bits/sec, 5627 packets/sec

     953098496 packets input, 1206543544279 bytes, 0 no buffer

     Received 664857 broadcasts (354055 multicast)

     0 runts, 0 giants, 0 throttles

     401342 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

     0 input packets with dribble condition detected

     477363643 packets output, 169391220601 bytes, 0 underruns

     0 output errors, 0 collisions, 0 interface resets

     0 babbles, 0 late collision, 0 deferred

     0 lost carrier, 0 no carrier

     0 output buffer failures, 0 output buffers swapped out

Here is the configuration of the two interfaces:

Catalyst 4500

interface GigabitEthernet7/45

description Trunk SERVERS2-2 0/47

switchport trunk encapsulation dot1q

switchport mode trunk

logging event link-status

Catalyst 2960

interface GigabitEthernet0/47

description Trunk CORE1 7/45

switchport mode trunk

media-type rj45

Do you have any idea of what could be causing the input errors?

Thanks in advance for your help.

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Edison Ortiz Tue, 11/25/2008 - 14:44
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You may be running into oversubscribed ports in the 4500. Remember the 6Gbps threshold per module on this chassis.

Have you tried moving this connection to another switchport and/or module and see if you can duplicate it?



alfonso.cornejo Tue, 11/25/2008 - 14:51
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Hi Edison,

I moved it to another switchport but not to another module, I'll try that tomorrow night and see what happen.

I'll post what happen.


richardpierce Thu, 08/13/2009 - 02:04
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I am experinecing the same problem, input errors only on the 4500 side of multiple links to core 6500s. Did you find a resolution to this?



alfonso.cornejo Thu, 08/13/2009 - 06:54
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Hi Richard,

The problem was that we were over the 6Gbps threshold per module on the 4500, we moved the connection to another module.

Hope this help.


richardpierce Fri, 08/14/2009 - 07:34
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How did you know you were over the 6Gbps threshold are there counters available to show this?


alfonso.cornejo Fri, 08/14/2009 - 07:41
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With a sh inter summary and manually add the RXBS and TXBS value from every interface on the module.


jbrenesj Thu, 08/13/2009 - 08:59
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"You may be running into oversubscribed ports in the 4500. Remember the 6Gbps threshold per module on this chassis."

I notice that there are no input/output drops on the interface so I doubt this is an oversubscription case.

What are those input errors??

I bet they are 1504 bytes dot1q frames.

Please paste a:

sh int gi7/45 counters all


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