Hi Joseph, On Thursday 07 May 2015 13:00:52 Joseph Zimmer wrote: > Hello, > > I am working with BATMAN-ADV and have successfully setup a mesh. In my > implementation of the mesh, the network requires BATMAN to operate in a > linear topology and ideally have node 1 hop to node 2 then through node 3 > and finally node 4. > > Node1 .Node2 ..Node3 Node4 > > In this network hops are preferred rather than distant links with low RSSI > values(-70). The problem that Im seeing is that the protocol chooses > routes that have the least hops but have RSSI values at about -78 to -90 > rather than routing through the closest node with RSSI values in the -50 > range. > > We adjusted the hop penalty to a low value (we used 1 and 0) and we did see > improvement with the hop selection but the throughput is very low due to an > RSSI of -64 or less. > > Questions: > > 1) Is there a way to adjust BATMAN using batctl to select routes based > on the RSSI value? > a. That is, choose to hop through a node with an RSSI of -50 and never > select a node that has a lower RSSI
Nope, BATMAN only uses packet loss as a metric. It could be possibly adjusted
to do so or low signal links could be filtered otherwise, but we would consider
that a bad hack.
There is another suggestion: You could increase the multicast rate to a high
value, e.g. 36 MBit/s or even higher. Higher rates only work with good
signals, and since batman-adv uses broadcasts (which is multicast for WiFi),
this will have a direct effect on your network.
> 2) Does the algorithm for route selection use RSSI in the calculation
> and if so can we modify the algorithm to increase the importance of RSSI in
> the selection?
It currently doesn't use RSSI
> 3) How do we gain access to the code to make these modifications?
Batman-adv is open source, and so is mac80211 and hopefully the WiFi driver
you use. However, it'd really suggest to start with tuning the multicast rate.
:)
Cheers,
Simon
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