[Olsr-dev] invalidate node links

Markus Kittenberger (spam-protected)
Fri Sep 30 10:55:43 CEST 2011

olsrd would drop all links if u take the interface down and not changing its
channel while it stays (logically) up all the time.

ip link set down dev wlan0
iwconfig wlan0 channel x
ip link set up dev wlan0

maybe iwconfig does not work on an downed interface (depends on the wlan
driver), than swap order of line 2 and 3,.


On Fri, Sep 30, 2011 at 10:49 AM, Giovanni Di Stasi <(spam-protected)>wrote:

>  Hi everyone,
> I would like to receive some advices regarding an experiment we are
> currently performing aboud channel assignment algorithms. The scenario is
> multi-radio.
> The channel assignment algorithm (centralized) triggers at a certain point
> the change of channels of most of the interfaces of nodes. It may happen
> that a neighbor which was reachable through one interface, after the change,
>  becomes reachable through another interface [1]. The experiment we are
> doing shows an interruption of approximately one minute before the TCP
> connections we had established are able to return to their full speed.
> This is due (I noticed that by taking a look at the Olsrd logs) to the time
> Olsrd needs to drop the old route (on the old interface) and use the new one
> (on the new interface).
> We would like to speed up things a little bit. The first attempt we think
>  to do is to reduce the Hello and TC Intervals. This would speed up the
> change but will imply greater overhead. First results however show no
> improvements.
> A different solution would be to discard all the links departing from the
> interface of which we have changed channel. If we change the channel of an
> interface, it means that all the links departing from that interface are
> (probably) no longer good, so it is good to drop them and start using new
> links (possibly just after the first hello packet is seen, so to regain
> rapidly connectivity). Do you agree on this solution?   If that's the case,
> how can I tell to Olsrd to drop all the links from a certain interface?
> Thanks a lot,
> Giovanni
> [1] suppose two nodes each with two interfaces, the one set on channel 1
> and the other on channel 2. After the channel change the first node starts
> using channels 3 and 4 and the second channels 4 and 3.
> --
> Olsr-dev mailing list
> (spam-protected)
> https://lists.olsr.org/mailman/listinfo/olsr-dev
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