Present

tldr -> babeld + iBGP full-mesh

I can just use Layer-3 VPN full-mesh instead, but i use babeld for future node-adding.

I dont enable reflect-kernel-metric in babeld, due to the god dammit compactable with BIRD. If you have solution, fell free to reach me.

Why not Layer-2 VPN?

They are either difficult to configure (compared to wireguard), unstable and not well accepted by the community, or unheard of for me.

Why not bird-babel-rtt?

Here's the reason, in Chinese. lol

Why not ... ?

...F**k off, i used it for a while and seems to be ok. So i dont want to move.