<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML xmlns="http://www.w3.org/TR/REC-html40" xmlns:v =
"urn:schemas-microsoft-com:vml" xmlns:o =
"urn:schemas-microsoft-com:office:office" xmlns:w =
"urn:schemas-microsoft-com:office:word"><HEAD><TITLE>Bericht</TITLE>
<META http-equiv=Content-Type content="text/html; charset=iso-8859-1">
<META content="MSHTML 6.00.2800.1597" name=GENERATOR><!--[if !mso]>
<STYLE>v\:* {
BEHAVIOR: url(#default#VML)
}
o\:* {
BEHAVIOR: url(#default#VML)
}
w\:* {
BEHAVIOR: url(#default#VML)
}
.shape {
BEHAVIOR: url(#default#VML)
}
</STYLE>
<![endif]-->
<STYLE>@font-face {
font-family: Tahoma;
}
@font-face {
font-family: Verdana;
}
@page Section1 {size: 595.3pt 841.9pt; margin: 70.85pt 3.0cm 70.85pt 3.0cm; }
P.MsoNormal {
FONT-SIZE: 12pt; MARGIN: 0cm 0cm 0pt; FONT-FAMILY: "Times New Roman"
}
LI.MsoNormal {
FONT-SIZE: 12pt; MARGIN: 0cm 0cm 0pt; FONT-FAMILY: "Times New Roman"
}
DIV.MsoNormal {
FONT-SIZE: 12pt; MARGIN: 0cm 0cm 0pt; FONT-FAMILY: "Times New Roman"
}
A:link {
COLOR: blue; TEXT-DECORATION: underline
}
SPAN.MsoHyperlink {
COLOR: blue; TEXT-DECORATION: underline
}
A:visited {
COLOR: purple; TEXT-DECORATION: underline
}
SPAN.MsoHyperlinkFollowed {
COLOR: purple; TEXT-DECORATION: underline
}
SPAN.EstiloCorreo17 {
FONT-WEIGHT: normal; COLOR: maroon; FONT-STYLE: normal; FONT-FAMILY: Verdana; TEXT-DECORATION: none; mso-style-type: personal
}
SPAN.EstiloCorreo18 {
FONT-WEIGHT: normal; COLOR: maroon; FONT-STYLE: normal; FONT-FAMILY: Verdana; TEXT-DECORATION: none; mso-style-type: personal-reply
}
DIV.Section1 {
page: Section1
}
</STYLE>
<!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]--></HEAD>
<BODY lang=ES vLink=purple link=blue>
<DIV><SPAN class=979001815-07092007><FONT color=#0000ff size=2>The counter
rollover occurs when the snmp counter has reached its maximum. By default SNMP
uses 32bit counters. </FONT></SPAN></DIV>
<DIV><SPAN class=979001815-07092007><FONT color=#0000ff size=2>In a 32bit
counter the maximum number wich can be stored is 2^32-1. After this
the counter resets to 0 and starts counting up to ist maximum again. This reset
to 0 is called the counter rollover.</FONT></SPAN></DIV>
<DIV><SPAN class=979001815-07092007><FONT color=#0000ff size=2>MRTG has an build
in mechanism that deals with counter rollovers: When the current value of the
counter is lower then the previous value there must have been a counter
rollover. Because there is no way to detect if there has been 1 or more counter
rollover MRTG assumes there has been 1 rollover, </FONT></SPAN><SPAN
class=979001815-07092007><FONT color=#0000ff size=2>and in the calculations the
counter maximum is added to the current value. </FONT></SPAN></DIV>
<DIV><SPAN class=979001815-07092007></SPAN><SPAN class=979001815-07092007><FONT
color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=979001815-07092007><FONT color=#0000ff size=2>Counter rollovers
occur frequently: When polling your target once per 5 minutes the rate per
second is:</FONT></SPAN></DIV>
<DIV><SPAN class=979001815-07092007><FONT color=#0000ff size=2>(current poll
value - previous poll value) / 300 seconds.</FONT></SPAN></DIV>
<DIV><SPAN class=979001815-07092007><FONT color=#0000ff size=2>When doing some
calculalations you will find the counter rollover occurs every 5 minutes with
a bandwith usage of about 114Mbit/s.</FONT></SPAN></DIV>
<DIV><SPAN class=979001815-07092007> </SPAN></DIV>
<DIV><SPAN class=979001815-07092007><FONT color=#0000ff size=2>
<DIV><SPAN class=979001815-07092007><FONT color=#0000ff size=2>When graphing
multiple target from one targetline there is a chance for a counter
rollover in each individual target. This is where MRTG fails to graph the rate
correctly: It can not know how many counter rollovers have occured in the last
polling interval. </FONT></SPAN></DIV>
<DIV><SPAN class=979001815-07092007><FONT color=#0000ff size=2>What makes things
even worse: When one counter rollover occured on one of the targets, and
the other targets together processed enough data to compensate this rollover it
is not even possible to detect the only one rollover! </FONT></SPAN></DIV>
<DIV><SPAN class=979001815-07092007>
<DIV><SPAN class=979001815-07092007><FONT color=#0000ff size=2>When using 64bit
counters the limits are way higher, but the basic problem will be the
same.</FONT></SPAN></DIV></SPAN></DIV>
<DIV><SPAN class=979001815-07092007></SPAN> </DIV>
<DIV><SPAN class=979001815-07092007>When storing the data in rrd format, the
data for each individual target is stored after the counter rollover
calculation. Now you can retrieve and summarize the data in a more reliable
way.</SPAN></DIV>
<DIV><SPAN class=979001815-07092007></SPAN> </DIV>
<DIV><SPAN class=979001815-07092007>HTH,</SPAN></DIV>
<DIV><SPAN class=979001815-07092007></SPAN> </DIV>
<DIV><SPAN class=979001815-07092007>Jan.</SPAN></FONT></SPAN></DIV></DIV>
<DIV><SPAN class=979001815-07092007><FONT color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=979001815-07092007><FONT color=#0000ff
size=2></FONT></SPAN> </DIV>
<BLOCKQUOTE style="MARGIN-RIGHT: 0px">
<DIV></DIV>
<DIV class=OutlookMessageHeader lang=nl dir=ltr align=left><FONT face=Tahoma
size=2>-----Original Message-----<BR><B>From:</B> NAP [mailto:nap@etecsa.cu]
<BR><B>Sent:</B> Friday, September 07, 2007 3:13 PM<BR><B>To:</B> Koelstra, J.
(Jan)<BR><B>Subject:</B> RE: [mrtg] Error in sum
interfaces<BR><BR></FONT></DIV>
<DIV class=Section1>
<P class=MsoNormal><FONT face=Verdana color=maroon size=2><SPAN lang=EN-GB
style="FONT-SIZE: 10pt; COLOR: maroon; FONT-FAMILY: Verdana">My sum is with 5
interfaces<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Verdana color=maroon size=2><SPAN lang=EN-GB
style="FONT-SIZE: 10pt; COLOR: maroon; FONT-FAMILY: Verdana">this my
Target. My problem will be here?<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Verdana color=maroon size=2><SPAN lang=EN-GB
style="FONT-SIZE: 10pt; COLOR: maroon; FONT-FAMILY: Verdana">Only show 3
interfaces<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Verdana color=maroon size=2><SPAN lang=EN-GB
style="FONT-SIZE: 10pt; COLOR: maroon; FONT-FAMILY: Verdana"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><B><FONT face=Verdana color=maroon size=2><SPAN lang=EN-GB
style="FONT-WEIGHT: bold; FONT-SIZE: 10pt; COLOR: maroon; FONT-FAMILY: Verdana">Target[myrouter]:
/x.x.x.x:public@a.b.c.d:::::2:+/y.y.y.y:public@a.b.c.e:::::2:+/z.z.z.z:public@a.b.c.f:::::2:<o:p></o:p></SPAN></FONT></B></P>
<P class=MsoNormal><FONT face=Verdana color=maroon size=2><SPAN lang=EN-GB
style="FONT-SIZE: 10pt; COLOR: maroon; FONT-FAMILY: Verdana"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Verdana color=maroon size=2><SPAN lang=EN-GB
style="FONT-SIZE: 10pt; COLOR: maroon; FONT-FAMILY: Verdana">I’m beginner in
mrtg and don’t understand what do you say with <I><SPAN
style="FONT-STYLE: italic">counters rollovers</SPAN></I> and <I><SPAN
style="FONT-STYLE: italic">rrd for backend
it<o:p></o:p></SPAN></I></SPAN></FONT></P>
<P class=MsoNormal><I><FONT face=Verdana color=maroon size=2><SPAN lang=EN-GB
style="FONT-SIZE: 10pt; COLOR: maroon; FONT-STYLE: italic; FONT-FAMILY: Verdana"><o:p> </o:p></SPAN></FONT></I></P>
<P class=MsoNormal><FONT face=Verdana color=maroon size=2><SPAN lang=EN-GB
style="FONT-SIZE: 10pt; COLOR: maroon; FONT-FAMILY: Verdana">Tell me about my
Target, and what I could do?<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Verdana color=maroon size=2><SPAN lang=EN-GB
style="FONT-SIZE: 10pt; COLOR: maroon; FONT-FAMILY: Verdana"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Verdana color=maroon size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: maroon; FONT-FAMILY: Verdana">So Thanks.
<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Verdana color=maroon size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: maroon; FONT-FAMILY: Verdana"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Verdana color=maroon size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: maroon; FONT-FAMILY: Verdana"><o:p> </o:p></SPAN></FONT></P>
<DIV>
<DIV class=MsoNormal style="TEXT-ALIGN: center" align=center><FONT
face="Times New Roman" size=3><SPAN style="FONT-SIZE: 12pt">
<HR tabIndex=-1 align=center width="100%" SIZE=2>
</SPAN></FONT></DIV>
<P class=MsoNormal><B><FONT face=Tahoma size=2><SPAN
style="FONT-WEIGHT: bold; FONT-SIZE: 10pt; FONT-FAMILY: Tahoma">De:</SPAN></FONT></B><FONT
face=Tahoma size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Tahoma">
Koelstra, J. (Jan) [mailto:JKoelstra@MINSZW.NL] <BR><B><SPAN
style="FONT-WEIGHT: bold">Enviado el:</SPAN></B> viernes, 07 de septiembre de
2007 4:33<BR><B><SPAN style="FONT-WEIGHT: bold">Para:</SPAN></B> NAP;
mrtg@lists.oetiker.ch<BR><B><SPAN style="FONT-WEIGHT: bold">Asunto:</SPAN></B>
RE: [mrtg] Error in sum interfaces</SPAN></FONT><o:p></o:p></P></DIV>
<P class=MsoNormal><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt"><o:p> </o:p></SPAN></FONT></P>
<DIV>
<P class=MsoNormal><FONT face="Times New Roman" color=blue size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: blue">How do you create the graph with the
sum?</SPAN></FONT><o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><FONT face="Times New Roman" color=blue size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: blue">When using a cfg file with Target: <A
href="mailto:oidx@a.b.c.d">oidx@a.b.c.d</A> + <A
href="mailto:oidy@a.b.c.d">oidy@a.b.c.d</A> + ... you will almost certain run
into problems with counter rollovers.</SPAN></FONT><o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><FONT face="Times New Roman" color=blue size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: blue">Without rrd for backend it isn't possible
to create summarized graphs of (bandwith-)rates that are 100%
accurate. </SPAN></FONT><o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt"> <o:p></o:p></SPAN></FONT></P></DIV>
<DIV>
<P class=MsoNormal><FONT face="Times New Roman" color=blue size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: blue">HTH,</SPAN></FONT><o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt"> <o:p></o:p></SPAN></FONT></P></DIV>
<DIV>
<P class=MsoNormal><FONT face="Times New Roman" color=blue size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: blue">Jan.</SPAN></FONT><o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt"> <o:p></o:p></SPAN></FONT></P></DIV>
<DIV>
<P class=MsoNormal><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt"> <o:p></o:p></SPAN></FONT></P></DIV>
<BLOCKQUOTE style="MARGIN-TOP: 5pt; MARGIN-BOTTOM: 5pt; MARGIN-RIGHT: 0cm">
<P class=MsoNormal style="MARGIN-BOTTOM: 12pt"><FONT face=Tahoma
size=2><SPAN lang=NL
style="FONT-SIZE: 10pt; FONT-FAMILY: Tahoma">-----Original
Message-----<BR><B><SPAN style="FONT-WEIGHT: bold">From:</SPAN></B>
mrtg-bounces@lists.oetiker.ch [mailto:mrtg-bounces@lists.oetiker.ch]
<B><SPAN style="FONT-WEIGHT: bold">On Behalf Of </SPAN></B>NAP<BR><B><SPAN
style="FONT-WEIGHT: bold">Sent:</SPAN></B> Wednesday, September 05, 2007
7:52 PM<BR><B><SPAN style="FONT-WEIGHT: bold">To:</SPAN></B>
mrtg@lists.oetiker.ch<BR><B><SPAN
style="FONT-WEIGHT: bold">Subject:</SPAN></B> [mrtg] Error in sum
interfaces</SPAN></FONT><SPAN lang=NL><o:p></o:p></SPAN></P>
<P class=MsoNormal><FONT face=Verdana color=maroon size=2><SPAN lang=EN-GB
style="FONT-SIZE: 10pt; COLOR: maroon; FONT-FAMILY: Verdana">We have problem
with interface sums. The values in the independent graphics don’t correspond
to the total value that we graphic.<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Verdana color=maroon size=2><SPAN lang=EN-GB
style="FONT-SIZE: 10pt; COLOR: maroon; FONT-FAMILY: Verdana">The file .cfg
of independent interfaces and the sum graphic is the
same.<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Verdana color=maroon size=2><SPAN lang=EN-GB
style="FONT-SIZE: 10pt; COLOR: maroon; FONT-FAMILY: Verdana">What will be
the problem?<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Verdana color=maroon size=2><SPAN lang=EN-GB
style="FONT-SIZE: 10pt; COLOR: maroon; FONT-FAMILY: Verdana">We need
help<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Verdana color=maroon size=2><SPAN lang=EN-GB
style="FONT-SIZE: 10pt; COLOR: maroon; FONT-FAMILY: Verdana"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Verdana color=maroon size=2><SPAN lang=EN-GB
style="FONT-SIZE: 10pt; COLOR: maroon; FONT-FAMILY: Verdana">Thanks,
<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Verdana color=maroon size=2><SPAN lang=EN-GB
style="FONT-SIZE: 10pt; COLOR: maroon; FONT-FAMILY: Verdana"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Verdana color=maroon size=2><SPAN lang=EN-GB
style="FONT-SIZE: 10pt; COLOR: maroon; FONT-FAMILY: Verdana"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><I><FONT face=Verdana color=teal size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: teal; FONT-STYLE: italic; FONT-FAMILY: Verdana"><o:p> </o:p></SPAN></FONT></I></P>
<P class=MsoNormal><I><FONT face=Verdana color=teal size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: teal; FONT-STYLE: italic; FONT-FAMILY: Verdana"><o:p> </o:p></SPAN></FONT></I></P>
<P class=MsoNormal><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt"><o:p> </o:p></SPAN></FONT></P></BLOCKQUOTE></DIV>
<TABLE>
<TBODY>
<TR>
<TD bgColor=#ffffff><FONT
color=#000000>_________________________________________________________<BR><BR>Dit
bericht kan informatie bevatten die niet voor u is bestemd. Indien u
niet de geadresseerde bent of dit bericht abusievelijk aan u is
toegezonden, wordt u verzocht dat aan de afzender te melden en het
bericht te verwijderen. De staat aanvaardt geen aansprakelijkheid voor
schade, van welke aard ook, die verband houdt met risico's verbonden aan
het elektronisch verzenden van
berichten.<BR>_________________________________________________________<BR><BR>This
message may contain information that is not intended for you. If you are
not the addressee or if this message was sent to you by mistake, you are
requested to inform the sender and delete the message. The state accepts
no liability for damage of any kind resulting from the risks inherent in
the electronic transmission of
messages.<BR>_________________________________________________________<BR></FONT></TD></TR></TBODY></TABLE></BLOCKQUOTE></BODY></HTML>
<table><tr><td bgcolor=#ffffff><font color=#000000>_________________________________________________________<br>
<br>
Dit bericht kan informatie bevatten die niet voor u is bestemd. Indien u niet de geadresseerde bent of dit bericht abusievelijk aan u is toegezonden, wordt u verzocht dat aan de afzender te melden en het bericht te verwijderen. De staat aanvaardt geen aansprakelijkheid voor schade, van welke aard ook, die verband houdt met risico's verbonden aan het elektronisch verzenden van berichten.<br>
_________________________________________________________<br>
<br>
This message may contain information that is not intended for you. If you are not the addressee or if this message was sent to you by mistake, you are requested to inform the sender and delete the message. The state accepts no liability for damage of any kind resulting from the risks inherent in the electronic transmission of messages.<br>
_________________________________________________________<br>
</font></td></tr></table>