So I've been reading up on large mesh networks out of curiosity and I'm not sure I fully understand how routing works. I know that Babel seems to be the go to protocol for doing routing in a large network with wireless links but I'm trying to understand how it is used in practice.
From what I understand Libremesh works by putting babel into one giant Batman Adv vlan. What I don't understand is how the actual communication happens in that vlan. Wouldn't you still be in layer 2 and thus need arp? In a network with thousands of nodes it seems like the performance would tank. Do I understand this right or am I missing something?
So am I correct in assuming that Babel is just the protocol that can be used for routing in a layer 2 medium?
Babel is a routing protocol. So it operates on layer 3 and makes neighbor reachable information. How to reach a network.
Batman is a large distributed layer2 switch.
Everyone who is still doing it in larger networks complains and needs a shitload of workarounds to make the network stable....
If you do not need "global" layer2 reachability, then please plan and build your network with layer3 islands which get interconnected.
Btw: for anyone considering using the Babel routing protocol, please consider using it with bird2, see https://bird.network.cz/?get_doc&v=30&f=bird-6.html#ss6.2
As far as I know of, all the implementation of Babel related RFC happens on bird2.
1 Like