Re: Per sta interfaces in WDS (4-address) mode

[Felix Fietkau <nbd@openwrt.org>]

On 2012-08-20 5:13 PM, Pavel Roskin wrote:
> On Sun, 19 Aug 2012 21:51:27 +0400
> Sergey Ryazanov <ryazanov.s.a@gmail.com> wrote:
> 
>> Hello dear all,
>> 
>> please tell me, why in the WDS mode, the stack creates a new interface
>> for each WDS station, and this interface hostapd adds to the parent AP
>> interface bridge? Why we couldn't simply pass this frames via AP
>> interface?
> 
> You may want to use a completely different IP address and netmask on the
> WDS interface.  Using the AP interface would take away that option.
> 
> hostapd is not a part of the kernel.  It should be possible not to add
> WDS interfaces to the bridge.
It's not just that. If the WDS station communication were done over the
AP interface, mac80211 would have to keep a table of which MAC address
is reachable behind which WDS station, which is something that the
bridge layer is supposed to do.
I've seen such a design mistake in various drivers, and I've seen the
weird quirks that this usually produces in more complex network
topologies ;)

- Felix