7206VXR Router. Interface errors

Unanswered Question
Mar 25th, 2009


We are getting reports from Cisco Works that one of the interfaces on the router is getting InputPacketErrorPct 18%.

I have tried chafing the cable (just incase).

Any idea's what I could try next?

I have this problem too.
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jorge.calvo Wed, 03/25/2009 - 16:00


Could you please include the output from show interface x/y and show controllers from the affected interface?

This would help to check interface configuration, type and other kind of errors detected.

uwic2 Thu, 03/26/2009 - 02:20

Thanks for the reply.

The output of our interface is:

FastEthernet2/1 is up, line protocol is up

Hardware is i82543 (Livengood), address is 0009.7bcd.b439 (bia 0009.7bcd.b439)

Description: TEST INT - DO NOT USE!!!

Internet address is xxx.xxx.xxx.xxx/30

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

reliability 255/255, txload 7/255, rxload 30/255

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

Full-duplex, 100Mb/s, 100BaseTX/FX

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

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

Last clearing of "show interface" counters 15:56:32

Input queue: 0/75/9744/1 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: Class-based queueing

Output queue: 0/1000/64/0 (size/max total/threshold/drops)

Conversations 0/7/256 (active/max active/max total)

Reserved Conversations 1/1 (allocated/max allocated)

Available Bandwidth 35000 kilobits/sec

5 minute input rate 11894000 bits/sec, 1433 packets/sec

5 minute output rate 2862000 bits/sec, 1011 packets/sec

56427775 packets input, 48843409414 bytes

Received 13666375 broadcasts, 0 runts, 0 giants, 44 throttles

1058203 input errors, 0 CRC, 0 frame, 4654 overrun, 1053549 ignored

0 watchdog

0 input packets with dribble condition detected

46422233 packets output, 36544074819 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

I can not show the device next in the chain as we have no access to it.

Could ibe that they have set speed and duplex to auto where as we haveset them to 100 and full?


jorge.calvo Thu, 03/26/2009 - 16:07


Your input errors are the sum of the overrun plus the ignored errors.

Both, overrun and ignored may indicate the FastEthernet hardware buffers cannot handle all the incoming packets.

I also notice you have 24.21% broadcast packets coming the device connected to the interface. This could also overload the interface hardware buffers causing the input errors.

My suggestion is to find out if there are any broadcast storm or problem in the LAN.


uwic2 Mon, 03/30/2009 - 01:59

Thanks for your help with this Jorge.

A bit more info.

The interface connects to a 2800 router then from that to the internet. We used to go straight out onto the internet, then the people who matter decided to put in a "demarcation point" (2800 router) as we have a new company who manages out internet connection.

To my mind, we started getting the problems as soon as the 2800 router got put in.

I'm going to put a HUB in-between our 7200 router and our network and run a packet sniffer. Hopefully this should show us something!

Any other ideas greatly appreciated.


Giuseppe Larosa Mon, 03/30/2009 - 02:06

Hello Jamie,

be aware that an hub is only able of half duplex operation: if you insert it the performance can further degrade.

you should use a LAN switch and some port mirroring to capture traffic between the two routers.

you can find that inserting a switch provides benefits.

The C2800 can be a bottleneck

Hope to help


uwic2 Mon, 03/30/2009 - 02:19

Hi Giuseppe,

We have a HUB that does full duplex or so it says on the interface that are connected. Even if it isn't it for a 15min test it should only throw up a few erros shouldn't it?

I'll have a look at port mirroring as well.



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