Hi,

First of all, just wanted to forward this awesome diagram regarding MTUs in Gluon-Setups which Freifunk Hamburg created :D :

https://twitter.com/ohrensesselnet/status/789176399655350272

Which might be helpful for anyone new to understand how the encapsulation in batman-adv works and how the MTU recommendations of the underlying hard interfaces are calculated.

(I need to ask Leo for the sources, maybe a version without the fastd overhead might be interesting for an MTU-explained page in the open-mesh.org wiki :)?)

While checking the calculations Freifunk Hamburg did, I was wondering whether the batadv_hardif_min_mtu() function should add an extra 4 bytes for VLAN tagged, encapsulated payload to the MTU calculations and the kmesg recommendations, especially since Antonio's great work made TT fully VLAN-aware?

Open-Mesh.com/Cloudtrax routers are using the VLAN awareness, right? Is the wifi interface MTU there just set to +4 bytes over the kmesg recommedation?

Regards, Linus