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<p class=MsoPlainText><font size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'>The whole network contain 10 nodes
in fixed positions, in outdoor environment, using olsrd v.0.4.10. </span></font><font face=Arial><span style='font-family:Arial'>Each node has about 3 neighbours,
and the maximum distance between nodes is 3 hops. The problem we experienced is
that routes are not stable.</span></font></p>
<p class=MsoPlainText><font size=2 color=black face=Arial><span style='font-size:10.0pt;font-family:Arial;color:black'> </span></font></p>
<p class=MsoPlainText><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>This seems related to the fact that some neighbours are
listed as non-symmetric (they appear as symmetric for some moments, then appear
as asymmetric, then again as symmetric). The percentage of lost packets over
these asymmetric links, however, is 0% in both directions. In the past weeks we
have made several tries (modifying the validity and emission time of Hello and
Tc messages, using link quality and hysteresis, etc), but the routes are still
unstable using these modifications.</span></font></p>
<p class=MsoPlainText><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> </span></font></p>
<p class=MsoPlainText><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>We have then decided to make further tests with a subset of
this network, with only three nodes. The situation in this case is better, but
routes are still *not* stable even in this small network. We observed the
routes for about 20 seconds each time. With a total number of 68 observations,
routes have been changed 10 times, which means 14.7% of the times. When we ran
ping among nodes the percentage of lost packets is 0%, but the round trip time
varies from 1 ms to 45 ms.</span></font></p>
<p class=MsoPlainText><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> </span></font></p>
<p class=MsoPlainText><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Attached to this message you can find the output of commands
iptable, ip and iwconfig on the three nodes, as well as the contents of the
olsrd.conf file. A few small notes: we have copied the *current* contents of
the olsrd.conf file but, as mentioned previously, we have already tried
different configurations, including LQ. The network nodes are Linux boxes using
a small Linux image derived from OpenWrt, where only a few packages are
installed and sometimes with limited options (in particular, this is relevant
for the ip package, as you can see in the attached text files).</span></font></p>
<p class=MsoPlainText><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> </span></font></p>
<p class=MsoPlainText><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>In this phase of our work, we would like to find measures
for improving link stability, e.g. by using directional antenna, higher antenna
gain, better interference protection, etc, but staying with olsrd 0.4.10. Do
you have any hits on how to achieve high link stability, including both
hardware and software measures? What is the main reason for the above described
link instability problem?</span></font></p>
<p class=MsoPlainText><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> </span></font></p>
<p class=MsoPlainText><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Thanks a lot in advance.</span></font></p>
<p class=MsoPlainText><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> </span></font></p>
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