[Olsr-dev] Freifunk Testing
Sat Jun 14 22:47:01 CEST 2008
> btw: Is there a reason for an TC Interval of 2 at an HELLO Interval of 5? that
> would be 2 TCs before the linkcost of a link could change...
there is. This is to avoid routing loops even when links are saturated
with payload traffic. Not all TC updates are likely to come through
under these circumstances, so redundancy helps here. (But even when
sending TCs twice as frequently as Hellos, Olsrd did loop occasionally
when we were testing it at the Meraka 'Massive Mesh' grid under high
payload.) To get entirely rid of routing loops, TC redundancy has to be
even greater. But the resulting protocol overhead is much more severe
then occasional routing loops that persist for a couple of seconds. This
is a limitation of the protocol design.
If you are not using Fisheye TC redundancy is of course very bad for a
large scale network.
Btw: There should be an option to disable the MPR algorithm completely.
It is superfluous anyway for Freifunk-like configurations since Wizard
of OS 2004. Setting MPR redundancy to 7 in the config is just a dirty
hack to get rid of the negative effects of MPR selection and the
problems that are growing out of it.
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