On Fri, Oct 28, 2011 at 11:10 AM, Arend Van Spriel <arend@xxxxxxxxxxxx> wrote: >> > I would expect this to affect the duration field in the >> > 802.11 header to indicate the shorter use of the medium. >> > Going through your patch I am not sure this is done. >> >> Hmmm. You're right, but that's something we already need to fix in many >> cases -- as the duration field is overwritten by most hardware these >> days, we haven't always maintained it very well. > > If the station still does the ACK we should not touch the duration field > in this case (see my reply to Helmut). The reason is the following: if you're running a mac80211 AP with multiple bssids, hostapd will answer to broadcast probe requests sent by STAs with one probe response per bssid (unicast of course). And since some clients stay only for a short amount of time on the scan-channel (a few ms) under some circumstances the probe responses aren't sent out yet before the scanning STA leaves the channel and thus retried till the maximum retry limit is reached. And these retries consume quite a lot of airtime. And to avoid this we just don't want to retry the probe responses in that case. Helmut -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
