[nsp] 7200, 12.0(21)S4 and "show int" counters?

[Gert Doering]

hi,

On Wed, Aug 21, 2002 at 08:35:16AM +0300, Pekka Savola wrote:
> On Wed, 21 Aug 2002, Gert Doering wrote:
> > is it just me, or has Cisco engineering reached a new all-time high in
> > "show int" counter brokenness?
> 
> Don't count on it.
> 
> This almost wins my favoourite:
> 
> ATM0/0/0 is up, line protocol is up
>   Hardware is cyBus ENHANCED ATM PA, address is 0010.2fcc.6800 (bia 0010.2fcc.6
>   [...]
>   5 minute output rate 1014029704 bits/sec, 1682 packets/sec
>   [...]
> 
> It's nice to know STM1 ATM managed to accelerate to 1 Gbit/s.. and big 
> packets those are, too! :-)

That's an old one :-) - I've seen that on our FastE's as well, bit rates
up to a Gbit.  I'm actually pretty sure what happens here - when the 32bit
byte counter wraps, it seems to overflow the bit rate calculation and
insert a huuuuuuge sample into the values used for this "5 minute decay" 
calculation.

I've had a script save away interface counters and output rate, and it
was reproduceable - every time the output counter wrapped, there was a
Gbit-"Burst" on the output rate.

> (This was fixed, at least for currently, somewhere between 12.0(15) and 
> 12.0(17)).

Yep.

I think that this one is actually excuseable in a way - there is a
calculation going on, with averaging and so, and a 32bit overflow is
happening which is something all programmers do in a while.

The other thing - counters not counting at all - I just can't understand.

gert
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Gert Doering - Munich, Germany                             gert@greenie.muc.de
fax: +49-89-35655025                        gert.doering@physik.tu-muenchen.de