<html><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px"><div><span>The MTU limit is on the olsr packet not on the whole IP packet. the total packet size is 128 + udp headers + IP headers. It's still a standard IPv4 packet with just a small payload - olsr packet.</span></div> <div class="qtdSeparateBR"><br><br></div><div class="yahoo_quoted" style="display: block;"> <div style="font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-size: 16px;"> <div style="font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-size: 16px;"> <div dir="ltr"> <font size="2" face="Arial"> On Friday, October 24, 2014 2:54 PM, Henning Rogge <hrogge@gmail.com> wrote:<br> </font> </div> <br><br> <div class="y_msg_container">On Fri, Oct 24, 2014 at 1:30 PM, Scoobi Doo <<a
shape="rect" ymailto="mailto:madroobalras@yahoo.com" href="mailto:madroobalras@yahoo.com">madroobalras@yahoo.com</a>> wrote:<br clear="none">> Hi,<br clear="none">> Your answer regarding using ETX code brings me back to another problem. I<br clear="none">> don't use ETX because i'm having simulations on narrowband nodes, which<br clear="none">> force me to change the size of the MTU (from 1500 to 128).<br clear="none"><br clear="none">Not sure an IP (especially IPv6) network with MTU 128 does work<br clear="none">well... you might need to think about layer-2 fragmentation.<br clear="none"><br clear="none">>When the network<br clear="none">> gets larger and the olsrd starts to fragment the messages (serialize<br clear="none">> functions) the routing table in ETX-mode is not correct in a simple<br clear="none">> full-mesh topology. From tests that i ran i saw that no matter what is the<br clear="none">> MTU size whenever the
network becomes larger so messages get fragmented, the<br clear="none">> olsrd fails to build the right routing table. When i use non-ETX code i<br clear="none">> don't see that problem.<br clear="none">> I prefer using ETX. did you encounter in such a problem?<br clear="none"><br clear="none">Most likely there is an "off by X" problem in the fragmentation<br clear="none">code... it most likely doesn't trigger on IPv4 because messages stay<br clear="none">small enough.<div class="yqt7825250160" id="yqtfd04237"><br clear="none"><br clear="none">Henning Rogge<br clear="none"></div><br><br></div> </div> </div> </div> </div></body></html>