Hi,
(copying cisco-nsp back in, maybe we'll manage to warn a few other readers
of the pitfalls... or annoy Cisco enough so that they go and fix it)
On Tue, Feb 12, 2002 at 08:10:52PM +1300, Andrew Cutler wrote:
> > <rant>
> > How broken can this get???
> Lots more. I have some 4500 that I recently started graphing with V2 and
> couldn't figure out why the graphs looked the same. So I started
> experimenting with walks and gets. The active interfaces are eth0(1),
> serial0(3) & serial1(4) Check out the following:
Oh, yes, we discovered that one quite a while ago.
Some platforms (if I remember correctly, it hits only the 4500) do not
implement counter64s, but don't tell you so - if you query the counter64,
it will always return the last counter32 that you have queried before.
Or maybe it was "if you query the counter64 on an *interface* that doesn't
support it, it will return the last counter64 value from the last c64-capable
interface queried".
So our tool has an check for IOS versions, and falls back to counter32
on those platforms (which is no big problem for us as those are low-speed
customer aggregation boxes).
[..]
> V1 snmpwalk the interfaces (works fine):
Yep...
> This was all on 12.0(19). So we set up another 4500 and tried it on
> 12.0(20), 21 and 21a with identical results. Then, just out of
> curiousity we tried 12.2(7) which came back with "no such object in the
> mib" for ifHCInOctets (does this mean 12.2 doewsn't support V2?). At
> this point we were so flabbergasted we gave up.
Counter64s are only supported on high-speed interfaces, not on "-T"s,
so our tool always queries both, and if no Counter64 exists, or if
it's 0, the Counter32 will be used.
Except on ATM subifs, of course, where it will *always* use Counter64,
as "0" could also mean "has just been resetted by 'clear count'" (yuck)...
> The good news is that this particular bug only seems to be happening on
> 4500's. Our 75/7200's don't seem to be affected, but I'll have to check
> the details of your message on them.
I have not seen this on any other platform or any other interface. Just
this single PA-E3 on this single 7206VXR/NPE-400, 12.0(19)S1...
gert
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Gert Doering - Munich, Germany gert@greenie.muc.de
fax: +49-89-35655025 gert.doering@physik.tu-muenchen.de
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