<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>Op 12 aug. 2012, om 22:26 heeft Markus Kittenberger het volgende geschreven:</div><br class="Apple-interchange-newline"><blockquote type="cite"><br><br><div class="gmail_quote">On Sun, Aug 12, 2012 at 2:06 PM, Michael Rack <span dir="ltr"><<a href="mailto:michael.rack@rsm-freilassing.de" target="_blank">michael.rack@rsm-freilassing.de</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<div><tt>All right! That figures :)<br>
<br>
So i try to adjust the vpn-interface mtu settings. I hope OLSR
splits messages, that gets bigger then the maximum mtu / mss.<br></tt></div></div></blockquote><div>afair olsr does not split existing messages!</div><div><br></div><div>it will just not combine olsr-messages to packets that are too big for the local interface mtu</div>
<div>(usually/often olsr-packets consist of multiple olsr-messages)</div><div><br></div><div>but if you have nodes that have enough neighbours to create > 1420 byte long messages, you have a problem.</div></div></blockquote><div>Why can't IP fragmentation handle >MTU packets?</div><div>If IP stack is unaware of MTU, there is a problem for all IP traffic.</div><div><br></div><div>Teco</div><br><blockquote type="cite"><div class="gmail_quote"><div><br></div>
<div>Markus</div><div><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div bgcolor="#FFFFFF" text="#000000"><div><tt>
<br>
Currently i use OLSR v0.6.2.<br>
<br>
<blockquote type="cite">DebugLevel 0<br>
IpVersion 4<br>
FIBMetric "flat"<br>
ClearScreen yes<br>
<br>
RtTable 100<br>
RtTableDefault 253<br>
<br>
AllowNoInt yes<br>
TosValue 16<br>
<br>
Willingness 3<br>
LinkQualityLevel 2<br>
LinkQualityAlgorithm "etx_ff"<br>
<br>
UseHysteresis no<br>
Pollrate 0.05<br>
NicChgsPollInt 3.0<br>
<br>
TcRedundancy 2<br>
MprCoverage 1<br>
<br>
InterfaceDefaults<br>
{<br>
...<br>
}<br>
</blockquote>
<br>
</tt><div class="im">
<pre cols="72">Liebe Grüße aus Freilassing,
Michael Rack
RSM Freilassing
--
RSM Freilassing Tel.: +49 8654 607110
Nocksteinstr. 13 Fax.: +49 8654 670438
D-83395 Freilassing <a href="http://www.rsm-freilassing.de/" target="_blank">www.rsm-freilassing.de</a> </pre></div>
Am 12.08.2012 01:09, schrieb Song Gao:<br>
</div><div><div class="h5">
<blockquote type="cite">
<div>Hey Michael,</div>
<div><br>
</div>
I am probably not the best person to answer this but from my
understanding, OLSRd uses MTU of the interface to decide packet
size. The interface created by VPN tunnel should be setting proper
MTU.
<div>
<br>
</div>
<div>Could you post your OLSRd config file as well as the version
of OLSRd you are using?<br clear="all">
<div><br>
</div>
<div><br>
</div>
<div>Kind regards,</div>
-- <br>
Song Gao<br>
<div><a href="https://profiles.google.com/song.gao.beta/about" target="_blank">https://profiles.google.com/song.gao.beta/about</a></div>
<br>
<br>
<br>
<div class="gmail_quote">On Sat, Aug 11, 2012 at 3:49 PM,
Michael Rack <span dir="ltr"><<a href="mailto:michael.rack@rsm-freilassing.de" target="_blank">michael.rack@rsm-freilassing.de</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi
OLSR-Users!<br>
<br>
I have a VPN-Tunnel that runs over a PPPoE-Link, so i have
only 1492 Bytes available. The VPN-Tunnel is established via
UDP, so i have 8 Bytes (MAC), and 12 Bytes (UDP) overhead.
So the remaining MTU is 1472 Bytes for the inner Layer-2.<br>
<br>
So there are 1452 Bytes left for OLSR.<br>
<br>
But OLSR currently send out packets with more then 1452
Bytes, so the VPN-Tunnel goes down and automatically get
reestablished.<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Aug 11 21:18:50 vtund[6598]: Session
neubichl-dsl-backup[79.192.xxx.xxx:46105] opened<br>
Aug 11 21:18:50 vtund[6598]: UDP connection initialized<br>
Aug 11 21:19:29 vtund[6598]: Message too long (90)<br>
Aug 11 21:19:29 vtund[6598]: Session neubichl-dsl-backup
closed<br>
</blockquote>
<br>
currently i drop packages over 1420 bytes that are passing
the DSL-Interface:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
iptables -A OUTPUT -o tap107 -m length --length 1420: -j
DROP<br>
</blockquote>
<br>
since that, the VPN-Tunnel is stable.<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
~ # ip route show table olsr-network | wc -l<br>
84<br>
</blockquote>
<br>
currently there are 84 routes spreaded over the whole
network via OLSR. That can not result in a so high package
size? How can i reduce the packet-size, or what have to be
done, so olsr does not eat up more then 1400 Bytes?<br>
<br>
<br>
Liebe Grüße aus Freilassing,<br>
<br>
Michael Rack<br>
RSM Freilassing<span><font color="#888888"><br>
-- <br>
RSM Freilassing Tel.: <a href="tel:%2B49%208654%20607110" value="+498654607110" target="_blank">+49 8654 607110</a><br>
Nocksteinstr. 13 Fax.: <a href="tel:%2B49%208654%20670438" value="+498654670438" target="_blank">+49 8654 670438</a><br>
D-83395 Freilassing <a href="http://www.rsm-freilassing.de/" target="_blank">www.rsm-freilassing.de</a><br>
<br>
<br>
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</font></span></blockquote>
</div>
<br>
</div>
</blockquote>
<br>
</div></div></div>
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