Open-Mesh » batman-adv

Scenario:
I have 2 dual radio APs (1 x 2.4GHz and 1 x 5GHz, both ath10k).
The APs are placed in two different rooms with various walls in between. Because of that meshing over 5GHz is quite unreliable.

Problem:
Batman-adv is often selecting the route going over the 5GHz radio because the tx rate (used to estimate the throughput) is often higher.
This route selection, however, turns out to be a very bad choice because the packet loss makes the 5GHz link unusable (I can hardly ping the other AP with batctl p).

(I wonder though, why is the tx rate often this high if packet loss is high as well...?)

Proposal:
One way to mitigate this issue would be to include the packet loss in the 1-hop link throughput estimation logic.
Mixing throughput and packet loss can be quite complicated, therefore I would like to keep it simple: i.e. when packet loss over a link is below 50%, drop the throughput to 0.1Mbps.
This way that link is heavily penalized and excluded from the routing (unless it's the only choice we have).

To measure the 1-hop packet loss we could either use the OGMs (similarly to what we did in B.A.T.M.A.N. IV, but it may become ugly quite fast) or we could rely on counting the received ELPs and sending back a periodic report to the sender.

Opinions? Comments?