[Olsr-dev] Idea for small OLSR improvement

[Mitar]

Hi!

I got an idea for small improvement in OLSR which I think could
improve its behavior in practical scenarios. The idea is to leave last
route node had to last peering node in place and do not remove it. So
if the node has many peers then there is no difference - OLSR is
choosing the best route. But once node has only one peering node and
it decides to remove route to it then I would recommend that we leave
it in place as it has the highest probability that this same route
will be restored (especially when nodes have fixed locations). And
maybe even some packets will get through (not so useful for TCP but
for UDP this is quite useful, like for streaming or telephony). Of
course whole mesh should also leave last known path in place so that
traffic can be routed back. Maybe it will be routed in wain, but maybe
something will come over.

If some other peering node gets route then at that time routes are
rewritten for that peering node.

With this we do not lose anything in the sense of optimal routing but
we get a little bit more of robustness.

(Of course this same laziness technique could be used also for other
routing protocols.)


Mitar