[smokeping-users] "how to read it" Part I

[Tobias Oetiker]

David,

I wrote this a few weeks agao for a guy who promised to maintain it
... he did not deliver ... so here is another try ...

tobi

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/_  __/_  / /  (_) Oetiker @ ISG.EE, ETZ J97, ETH, CH-8092 Zurich
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---------- Forwarded message ----------
From: Tobias Oetiker <oetiker at ee.ethz.ch>
To: Arturo Martin G. <Arturo.Martin at sync.com.ve>
Date: Wed, 11 Jun 2003 23:13:01 +0200 (MEST)
Subject: Re: Smokeping : "how to read it"

Today Arturo Martin G. wrote:

>
>          Hello Tobi :
>
>
>          First and foremost THANKS for the RRD/MRTG creation : probably the
> most popular piece of great software ever written for monitoring purpouses.
>
>          One of the biggest benefits of the original MRTG "traditional"
> graphs is its EASE to understand : it doesn´t take a Phd to make sense of
> most of the graphs. I've trying to understand the meaning of Smokeping and
> I just give up : don´t know if my speculations are correct.
>
>          Don't you have a "how to read an smokeping graph / potential
> applications for smokeping" kind of document ? I review everything online
> and (in your web page) I found nothing explanatory in this area.

Hi Arturo,

How about this, I will answer your questinons and you write a few
paragraphs so that others can profit too ?


Smokeping is a latency measurement tool. It sends test packets out
onto the net and measures the ammount of time they need to travel
from one place to the other and back.

For every round of measurement smokeping sends several packets. It
then sorts the different round trip times and selects the middle
one, this means when there are 10 times, time number 5 is selected
and drawn (median). The other times are drawn as successively
lighter shades of gray in the background (smoke).

Sometimes a test packet sent out but never returns. This is called
packet-loss. The color of the median line changes according to the
number of packets lost.

All this information together gives an indication of network
health. packet loss for example is something which should not
happen at all, it can mean that a device in the middle of the link
is overloaded or some routing configuration is wrong.

Regarding round trip time, if this fluktuates heavily (lots of
smoke) this also indicates that the network is overloaded.

Smokeping also has special probes to not just test roundtrip time
of the packet, but rather have it perform some task at the remot
end, eg download a webpage ... this will give a combined 'picture'
of webserver availablility and network health.

smokeping can also look at this data all on its own, and when it
sees a predefined pattern, it can send out email ... a pattern may
be packet loss going from < 1% to over 20% or something like this
...

any more questions ?

tobi



(median). Not the average,
>          Any suggestions ???
>
>
>          Saludos
>
>          Arturo
>
> _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/
>
>                  Arturo Martin G.
>                  SYNC Consultores C.A.
>
>                  Arturo.Martin at sync.com.ve
>                  http://www.sync.com.ve
>
>                  Tlfs : (212) 762-85-55/30-12/86-93 / Cel : (NUEVO /
> 15-1-03) 0416 626-36-63
>                  Fax : (212) 762-66-71
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>                          ICQ # : 173812572 / AIM (AOL) : amgsync
>
> _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/
>

-- 
 ______    __   _
/_  __/_  / /  (_) Oetiker @ ISG.EE, ETZ J97, ETH, CH-8092 Zurich
 / // _ \/ _ \/ /  System Manager, Time Lord, Coder, Designer, Coach
/_/ \.__/_.__/_/   http://people.ee.ethz.ch/~oetiker   +41(0)1-632-5286

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