<!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>
<META http-equiv=Content-Type content="text/html; charset=us-ascii">
<META content="MSHTML 6.00.2900.3354" 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;
}
@page Section1 {size: 595.3pt 841.9pt; margin: 72.0pt 90.0pt 72.0pt 90.0pt; }
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.EmailStyle17 {
COLOR: navy; FONT-FAMILY: Arial; mso-style-type: personal-reply
}
DIV.Section1 {
page: Section1
}
</STYLE>
</HEAD>
<BODY lang=EN-GB vLink=purple link=blue>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=861244413-10102008>I Totally agree with Steve and suggest that you put a
lot of effort, quickly, into finding out what product is eating your CPU.
Wireless is a good suspect especially if you are using GRE. If you are
using Cisco Wireless products don't let them tell you that your cpu issues are
being cause by snmp. Have you looked at upgrading your cpu and memory on
the 6500?</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=861244413-10102008>Good luck.</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=861244413-10102008></SPAN></FONT> </DIV><BR>
<DIV class=OutlookMessageHeader lang=en-us dir=ltr align=left>
<HR tabIndex=-1>
<FONT face=Tahoma size=2><B>From:</B> mrtg-bounces@lists.oetiker.ch
[mailto:mrtg-bounces@lists.oetiker.ch] <B>On Behalf Of </B>Steve
Shipway<BR><B>Sent:</B> Thursday, October 09, 2008 5:07 PM<BR><B>To:</B> 'Jack
Bauguer'; 'mrtg@lists.oetiker.ch'<BR><B>Subject:</B> Re: [mrtg] Can Mrtg cause a
Router to crash because of the snmp querys?<BR></FONT><BR></DIV>
<DIV></DIV>
<DIV class=Section1>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Our network here is way
larger (1500 switches, 60 routers, 1320 hosts), and we poll not only network
traffic but also stats for multicast traffic and CPU use on the core switches
and routers, all at 5min intervals. There is no discernable load on the
switches from the SNMP queries. Of course, our main switches are only on
about 20% load, but remember that these queries are only simple network traffic
ones.<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Note that, since SNMP
is UDP traffic, and low priority to a switch, the SNMP queries will simply be
dropped in favour of TCP traffic if a link is overloaded and not resent.
You’ll get greyout on your MRTG graphs (if using routers2) or blanks.
Most switches/routers will ignore SNMP queries in favour of forwarding
packets.<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">If your network is
running at 85% loading I’d say you have other more serious issues in capacity
planning to deal with! If a few SNMP queries every 5min would cause a
network collapse, then you’re at far more risk from (eg) someone opening a web
browser…<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Steve<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<DIV
style="BORDER-RIGHT: medium none; PADDING-RIGHT: 0cm; BORDER-TOP: medium none; PADDING-LEFT: 4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: blue 1.5pt solid; PADDING-TOP: 0cm; BORDER-BOTTOM: medium none">
<DIV>
<DIV class=MsoNormal style="TEXT-ALIGN: center" align=center><FONT
face="Times New Roman" size=3><SPAN lang=EN-US 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 lang=EN-US
style="FONT-WEIGHT: bold; FONT-SIZE: 10pt; FONT-FAMILY: Tahoma">From:</SPAN></FONT></B><FONT
face=Tahoma size=2><SPAN lang=EN-US
style="FONT-SIZE: 10pt; FONT-FAMILY: Tahoma"> mrtg-bounces@lists.oetiker.ch
[mailto:mrtg-bounces@lists.oetiker.ch] <B><SPAN style="FONT-WEIGHT: bold">On
Behalf Of </SPAN></B>Jack Bauguer<BR><B><SPAN
style="FONT-WEIGHT: bold">Sent:</SPAN></B> Friday, 10 October 2008
02:32<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] Can Mrtg cause a Router to crash because of the snmp
querys?</SPAN></FONT><SPAN lang=EN-US><o:p></o:p></SPAN></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>
<DIV>
<P class=MsoNormal><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt">Hi,<o:p></o:p></SPAN></FONT></P></DIV>
<DIV>
<P class=MsoNormal><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt">Im trying to build a traffic analyzer based on Mrtg here
for my company, (10 big routers 80 switches 80 servers
Cisco/Nortel).<o:p></o:p></SPAN></FONT></P></DIV>
<DIV>
<P class=MsoNormal><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt">There was an argument about creating this Mrtg-Server,
some people claim it would be suicidal, because many of the routers and switches
operates with heavy traffic and cpu load (about 75-85%) and querying these
elements every 5 minutes would collapse the
network.<o:p></o:p></SPAN></FONT></P></DIV>
<DIV>
<P class=MsoNormal><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt">Can somebody give me some feedback on this, I personally
dont believe that querying through snmp every 5 minutes can cause such damage on
the network, even if they are on high capacity, i think maybe it could cause a
small delay on the query but nothing else, right?. I have allready worked in a
smaller enviourment and had no problems, but I need some technical arguments to
convince these guys, <o:p></o:p></SPAN></FONT></P></DIV>
<DIV>
<P class=MsoNormal><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt">any ideas?<o:p></o:p></SPAN></FONT></P></DIV>
<DIV>
<P class=MsoNormal><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt">regards. JB<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></DIV><p></p><p>Please consider the environment before printing this e-mail. <br><br> CONFIDENTIAL NOTICE:<br>This e-mail message and any attachment(s) (collectively, this 'Email') are intended <br>only for the confidential use of the recipient(s) named above. If the reader of this <br>message is not the intended recipient named above or an agent responsible for <br>delivering it to the intended recipient named above, you have received this Email in error. <br>Please notify the sender immediately and permanently delete this Email and any copies thereof.</BODY></HTML>