From: Scott Morris (swm@emanon.com)
Date: Mon Jun 13 2005 - 03:09:22 GMT-3
Ok... Point taken. But it would be all in how it's worded.
If you are told to measure CPU utilization when to trigger an alarm when it
goes above 85%, but turn it off when it goes below 75% you are looking at
two absolute values.
If you are told to measure CPU utilization to trigger an alarm whenever it
varies by more than 40% between readings, you are looking at a delta value.
Scott
-----Original Message-----
From: Amit Jain [mailto:netsteps@rediffmail.com]
Sent: Monday, June 13, 2005 1:54 AM
To: Scott Morris; 'Roy Dempsey'; 'Hotmail'
Cc: 'Cisco certification'
Subject: Re: Absolute vs delta
Scott
I may also say that I indeed care, that two seconds ago my CPU utilization
was 20% and now its 82%. So in this case it may become delta.
Can you site some other example to differentiate, becasue it does create
confusion.
Thanks
Amit
----- Original Message -----
From: "Scott Morris" <swm@emanon.com>
To: "'Roy Dempsey'" <roy.dempsey@gmail.com>; "'Hotmail'"
<pauwen@hotmail.com>
Cc: "'Cisco certification'" <ccielab@groupstudy.com>
Sent: Sunday, June 12, 2005 9:30 PM
Subject: RE: Absolute vs delta
> I'm jumping into this discussion a little late here, so forgive me if
> someone has already pointed it out, but "absolute" or "delta" have to do
> with a reference point, not whether something is going up or going down.
> Your rising or falling thresholds have to do with the direction of
> measurements.
>
> You set up an RMON alarm to be monitored every 'x' number of seconds. The
> next stage is what you do with that number. If it is an absolute number,
> you simply measure that number itself with regards to your going up/down
> events. If it is a delta number, you measure it in reference to the last
> timed measurement and see the change value (hence "delta").
>
> CPU utilization as an example is typically an absolute measurement.
> Interface utilization, on the other hand may very well be a delta. (I
don't
> necessarily care that my interface is at 50% right now, but I do care if
two
> seconds ago I was at 1% and now I'm at 51%)
>
> HTH,
>
> Scott
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Roy
> Dempsey
> Sent: Sunday, June 12, 2005 8:05 AM
> To: Hotmail
> Cc: Cisco certification
> Subject: Re: Absolute vs delta
>
> Georg,
>
> It was actually a collegue, who had read it in a lab scenario. However
Brian
> McGahan from IE, in a reply to the group, seems to have confirmed that I
was
> indeed incorrect.
>
> It relates to whether the value being monitored can only rise, or whether
it
> can rise and fall. For example, the amount of errors seen on an interface
> will only increase, and should use delta.
>
> Values which rise and fall like CPU utilisation should use absolute
values,
> because the rate of change which delta examines isn't useful in these
cases,
> only the currently measured value.
>
> I think I have paraphrased Brian correctly. If not, I apologise.
>
> Do I understand it? I'm not sure yet....:-)
>
> Regards
> Roy
>
>
> On 6/11/05, Hotmail <pauwen@hotmail.com> wrote:
> > Hello Roy,
> >
> > I would have said the same as you, exceed means absolute, and increase
> > means delta. When you say you are being told otherwise, is that from
> > an exercise, or solution book ?
> >
> > Regards,
> >
> > Georg
> > ----- Original Message -----
> > From: "Roy Dempsey" <roy.dempsey@gmail.com>
> > To: "Cisco certification" <ccielab@groupstudy.com>
> > Sent: Thursday, June 09, 2005 6:14 PM
> > Subject: RMON: Absolute vs delta
> >
> >
> > > If a question asks to generate an RMON alert when the number of
> > > input errors on an interface exceeds 50 per second, should you use
> > > absolute or delta? This sounds like an absolute event, rather than a
> > > delta event.
> > >
> > > If it asked you to alert when the input errors *increased* by 50 per
> > > second I would have thought this was a delta event. However, I'm
> > > being told differently...
> > >
> > > Can anyone explain how you can differentiate between them?
> > >
> > > Thanks
> > > Roy
> > >
> > > ____________________________________________________________________
> > > ___ Subscription information may be found at:
> > > http://www.groupstudy.com/list/CCIELab.html
> > >
> >
>
>
> --
> Regards,
> Roy
>
> _______________________________________________________________________
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