[mrtg] Sorta OT, clear counters vs snmp was RE: Re: ODD spike

[Roth, Gabrielle]

> > > If so: counter reset (perhaps switch reset).
> > >
> > 	Switch didn't reset :
> > 
> > 	SWITCH uptime is 51 weeks, 2 days, 35 minutes
> 
> telnet to the switch, followed by "clear counters" ?
> 

Veering a bit OT here:
The OP mentioned a Cisco 2924 switch.  I apologize if what follows is really
obvious to the rest of you, it wasn't to me, but I'm still a relative newbie
with Cisco stuff.

There was a discussion several months ago about the relationship between the
numbers you see with "sh in" on a cisco box and the numbers that you get
from the interfaces MIB.  In a message to the list dated 18 July 2000,
Matthew Moore stated [paraphrased] that he had the word straight from Cisco
that the counters read by snmp are separate from the counters you get from
"sh in" (on a router); the snmp counters hold data from the time the box was
booted.  (There is a gap in the list archive between 6 July and 18 August.
Fortunately I made a hard copy of this message. :D  Matthew are you still on
the list?  Any comment?)

Because I am curious, I decided to check this out in our lab.

routers: 2651, 3640 X 2, 2514; switches: 6509, 5500, 2916, 1924

telnet to [box], send some pings to create some traffic because not much
goes on in the lab right now.
snmpwalk [box] [comm] interfaces > before
telnet to [box], clear counters
snmpwalk [box] [comm] interfaces > after
diff before after, look for lower numbers in after

X 3

Results:
"clear counters" reset the counters in the interfaces table in only the
6509, 5500 and the 1924.  Based on past experience with Cisco, I also expect
this to be OS dependent. :)

I realize that this doesn't solve the OP's problem but I wanted to bring
this up.

gabrielle

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