On Fri, 2011-01-21 at 15:35 +0200, ext Luciano Coelho wrote: > Hi Juuso, > > Just a quick comment/question: > > > On Tue, 2011-01-18 at 07:32 +0100, juuso.oikarinen@xxxxxxxxx wrote: > > From: Juuso Oikarinen <juuso.oikarinen@xxxxxxxxx> > > > > The passive scan channel dwell time currently used is 30ms-60ms. A typical > > beacon interval for AP's is 100ms. This leads to a ~30% worst-case probability > > of finding an AP via passive scanning. > > The beacon intervals are defined in TUs. > > > > For 5GHz bands for DFS frequencies passive scanning is the only scanning > > option. Hence for these, the probability of finding an AP is very low. > > > > To fix this, increase the passive channel scan dwell times (also the early > > leave value, as 5GHz channels are still typically very silent.) Use a value > > of 100ms, because that covers most typical AP configurations. > > In the firmware API, the dwell times are expressed in milli-TUs. So I > guess here you mean "use a value of 100 TUs", isn't it? > > Based on testing the probability of finding an AP (102.4ms beacon interval) on > > a single scan round are as follows (based on 100 iterations): > > Here you use milliseconds for the AP beacon interval. 102.4ms is 100 > TUs, so that's correct. > > It's just a bit confusing because of the slight difference between TUs > and msecs. Gery was wondering why you were using 100ms if the most > common beacon interval is 102.4ms (100 TUs). Of course, you're actually > using 100 TUs, so it's fine. > > I just think it's easier to follow if you forget msecs and use only TUs > in your explanation. > You're right. I'll convert the ms to mTU's in the description in v2. This is a bit unclear to me too, though, because I don't know exactly what the unit is we give the firmware. It's either TU/1024 or TU/1000. Some reference I saw way back claimed it was plain TU's, which obviously is not a possibility. -Juuso -- 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
