Re: [B.A.T.M.A.N.] No rebroadcast on mesh links

Linus Lüssing
2016-03-31T17:17:55Z

On Fri, Apr 01, 2016 at 12:01:41AM +0800, Antonio Quartulli wrote:
> On Thu, Mar 31, 2016 at 02:11:19PM +0200, Simon Wunderlich wrote:
> > I thought a little more on automation, but I'm now at a point to agree that
> > there is no good way to do it - at least I'm out of ideas. If anyone else has
> > some ideas, please speak up NOW. :)
>
> Some time ago we had a proposal (by Linus I believe) which was about detecting
> transitive interfaces by exchanging neighbour tables between peers. This way a
> node can understand if every other node behind an interface can talk to each
> other or not.

Basically the first ELP patches had provided that information
already, there was a table of neighbors together with the measured
link RX metric. But the ELP version merged now is simpler with less overhead
and does not have such a table anymore, as the link metric is now
provided by mac80211 / the rate selection algorithm.

> Although this approach sounds more complex, it would also help optimizing the wifi
> case: a node can understand if the hosts in an adhoc cells can all talk to each
> other and then avoid the retransmission (thus saving previous airtime - as we
> would save bandwidth in a VPN).

Indeed.

>
> The only problem is that this would work only after extending BATMAN V and would
> unlikely be implemented in BATMAN IV.

I wouldn't see it as a problem but a feature instead, helping to
motivate to migrate to BATMAN V ;). Also, Matthias provides Debian
packages for BATMAN IV which includes the manual switch, so
it shouldn't be too painful for BATMAN IV users either.

>
> Not sure if Linus (?) or anybody else is willing to work on this....but I guess
> people would like a solution to be used on BATMAN IV ? Or is this an option ?

Back then I think I said (and this is still the case) I would love
to work on a detection mechanism, but only once the multicast
things are finished. I don't want to drag multiple patchsets along
for years.

If anyone else wants to work on that, great :).