Question: if you have two #mikrotik #switches with #VLAN enabled (CRS317-1G-16S+RM) and you want to connect them via a #crosslink (sfpplus-16), to have a #failover switch (Debian uses tagged VLAN via bond0 with active-backup) and it works only, if you don't have VLAN at all, what can be the issue ? It works only if all Hosts have the active NIC on the same switch. If Host 1 has active on Switch 1 and Host 2 on Switch 2, network stops between them. Btw: MLAG is broken on #mikrotik since years.
@blog_reloaded Do you tag the VLANs on the crosslink?

@falk_ jupp, it was. But after killing two times the CORP network (hint: don't try this at home) (thanks to HomeOffice), it seems I've got it.

Maybe a good thing, to create a new Blog entry.

@blog_reloaded Accidentally ordered Mikrotik Switching Loops for breakfast?
@falk_ Yupp .. 4 or 5 times