On Monday, 25 February 2019 17:00:46 CET Linus Lüssing wrote:
[...]
> Disable batman-adv and try a broadcast ping like "ping6 ff02::1%adhoc0" and
> unicast ones. If that works with 6 nodes, but not with 7 ones then you
> know it's not batman-adv's fault.

This is only true when the driver/firmware handles multicast frames as 
broadcasts. I have already seen some of them converting the multicast/unicast 
frames to unicast frames in such situations. This also broke OGM detection on 
batman-adv because we only accept broadcast OGMs received as broadcast - 
otherwise the OGM metric stuff wouldn't make any sense at all.

And you have to do this in both directions to check whether bidirectional 
links are available. A ping6 answer (icmp echo reply) is unicast - and you 
also need the check the broadcast stuff in both direction.

But yes, when even this test fails then it is definitely not batman-adv's 
fault. Just keep in mind that a working ping6 doesn't have to mean that it is 
batman-adv's fault.

Kind regard,
	Sven