[c-nsp] Gigabit Interface Input Errors

[Sigurbjörn Birkir Lárusson]

Do a show controller Gi0/1 | i rx_resource

Chances are the input error count is the same as the rx_resource_error count

This is a microburst issue, and sadly, I know of no way to get around it,
the only solution is buying a router that is able to handle wirespeed Gig

BR,
Sibbi 


> From: Ivan Gasparik <ivan at ig.sk>
> Date: Fri, 13 Nov 2009 10:50:05 +0100
> To: <cisco-nsp at puck.nether.net>
> Subject: Re: [c-nsp] Gigabit Interface Input Errors
> 
> Hi folks,
> 
> Does anybody know what causes the router to drop packets as
> overrun and what as an input queue drops. There are two show interface
> examples of NPE-G1, both with input hold-queue set to 4096. The first
> one only shows 153 overrun packets, in the second interface output
> you can see overruns together with input queue drops:
> 
> GigabitEthernet0/1 is up, line protocol is up
> ...
>   Input queue: 0/4096/0/58537 (size/max/drops/flushes); Total output drops: 0
>   Queueing strategy: fifo
>   Output queue: 0/4096 (size/max)
>   1 minute input rate 43040000 bits/sec, 6944 packets/sec
>   1 minute output rate 23483000 bits/sec, 7180 packets/sec
>      2609205324 packets input, 3131277093 bytes, 6 no buffer
>      Received 2871721 broadcasts (0 IP multicasts)
>      0 runts, 0 giants, 2 throttles
>      153 input errors, 0 CRC, 0 frame, 153 overrun, 0 ignored
>      0 watchdog, 2871721 multicast, 0 pause input
> 
> GigabitEthernet0/3 is up, line protocol is up
> ...
>   Input queue: 0/4096/4258004/961350 (size/max/drops/flushes); Total output
> drops: 44638280
>   Queueing strategy: Class-based queueing
>   Output queue: 6/4096/0 (size/max total/drops)
>   1 minute input rate 15685000 bits/sec, 5120 packets/sec
>   1 minute output rate 28836000 bits/sec, 5171 packets/sec
>      2503236491 packets input, 208082741 bytes, 589462 no buffer
>      Received 1329388071 broadcasts (13 IP multicasts)
>      0 runts, 12 giants, 960 throttles
>      128042 input errors, 12 CRC, 0 frame, 128018 overrun, 0 ignored
>      0 watchdog, 1424143105 multicast, 0 pause input
> 
> Thanks
> Ivan
> 
> 
> On Thursday 05 November 2009 21:38:53 Gert Doering wrote:
>> Hi,
>> 
>> On Thu, Nov 05, 2009 at 01:41:16PM -0500, Drew Weaver wrote:
>>> Does anyone have any tips on finding out what is causing it to
>>> overrun?
>> 
>> "Hardware too slow error" - packets arrive in short bursts at line rate,
>> and your router cannot handle that.
>> 
>> For example, an NPE-G1 will handle packets at, say, 300 mbit/sec if they
>> come in evenly spaced - packet<pause>packet<pause>packet<pause> - but if
>> 1000 packets arrive back-to-back and then a longer pause, it will
>>  overrun the buffers.
>> 
>> There's not much you can do, except "get a hardware forwarding box"
>> or "just accept it, and only worry if the errors increase more
>>  frequently".
>> 
>> We do some of both :-)
>> 
>> gert
>> 
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