forwarding works fine with 802.1ad vlans

forwarding works fine with 802.1ad vlans

[pony]

Hello,

In https://www.open-mesh.org/projects/batman-adv/wiki/Faq#VLAN-forwarding-doesnt-work it is stated that batman advanced will only forward vlan frames when it knows about the vlan. However this seems only to be true for 802.1q vlans. I was able to send 802.1ad tagged frames over the mesh without configuring any vlans on top of the soft interface. I am using batman-adv 2022.0-openwrt-6. When I try the same with 802.1q it behaves as described in the wiki page.
This may be be problematic when people rely on batman advanced not forwarding vlan tagged frames.

Kind regards,
pony

Re: forwarding works fine with 802.1ad vlans

[Linus Lüssing]

Hi pony,

Thanks for the feedback! I've added a comment to this Wiki entry,
that you should not rely on packets being filtered.

I'm not sure if this filtering is 100% intentional or just a
byproduct of the early VLAN awareness implementation. So far we
typically advertised batman-adv as "it just works/behaves like a
(virtual) switch", which usually helps people to understand what
to expect or not to expect from a layer 2 mesh routing protocol.
And typically, a switch in its default configuration would not
drop VLAN tagged frames.

There are/were plans to autodetect VLANs, I think, so that
you wouldn't need to add something like a bat0.23 manually. But so
far nobody has implemented it.

Regards, Linus


On Sun, Jul 02, 2023 at 04:33:55PM +0000, pony wrote:
> Hello,
> 
> In https://www.open-mesh.org/projects/batman-adv/wiki/Faq#VLAN-forwarding-doesnt-work it is stated that batman advanced will only forward vlan frames when it knows about the vlan. However this seems only to be true for 802.1q vlans. I was able to send 802.1ad tagged frames over the mesh without configuring any vlans on top of the soft interface. I am using batman-adv 2022.0-openwrt-6. When I try the same with 802.1q it behaves as described in the wiki page.
> This may be be problematic when people rely on batman advanced not forwarding vlan tagged frames.
> 
> Kind regards,
> pony
> 
>