Re: [Madwifi-users] madwifi and bridging

[Jim T. <ji...@ne...>]

>
> The reason for this is that every frame must be acknowledged by the 
> receiver (the AP when

most frames must be ACKed.   group-addressed frames, some control 
frames and some management frames need not be ACKed.

>  working in managed mode, or another client when working in ad-hoc 
> mode). The ACK is sent to the MAC address that is given as sender.

I think, properly, you should refer to "addr2", rather than 'sender'.

You may want to also mention 'FromDS' and 'ToDS'.

> If the MAC address is a MAC from the ethernet behind a WLAN client, 
> that WLAN client will ignore the ACK (as it isn't addressed) and 
> resend the last frame, as it believes that the receiver didn't get it.

There are problems with addr1 as well.   addr1 identifies the 
(ultimate) endpoint, possibly
behind an AP or bridge.

> Bridging needs extended address formats, allowing to send the ACKs to 
> the correct WLAN station. These are either three or four address 
> headers, and both are not available for managed mode.

I'd have to check, but I don't think the standard disallows sending 
4-address frames in 'managed (BSS) mode'.