Re: [RFC V2 1/5] nl80211: allow reporting RTT information in scan results
On 30-11-2016 9:22, Johannes Berg wrote: > On Mon, 2016-11-28 at 21:07 +0100, Arend Van Spriel wrote: >> >> I was wondering about the meaning of the term "parent_bssid". Given >> your remark it means something else than my guess. I actually meant >> the distance to the AP indicated by this BSS. Our gscan code obtains >> the gscan results from firmware and in that API it has RTT info. > > Oh, ok. Right, that's unrelated to the parent_bssid. > > I do wonder how it'd even be possible to *determine* this though? > Perhaps by the ACK timing, assuming it's precise on the AP? There is 11v, 11mc, and some proprietary flavor we call 1-way TOF. However, I do not expect those measurements to be done during the scan procedure as it would affect duration of the whole scan exercise. >> However, recent testing revealed those fields are always coming up >> with zero values :-( > > Heh :-) > >> So right now I am not sure if we need this extension. > > FWIW, we don't seem to have it. I will drop this in next RFC round. Regards, Arend
Re: [RFC V2 1/5] nl80211: allow reporting RTT information in scan results
On Mon, 2016-11-28 at 21:07 +0100, Arend Van Spriel wrote: > > I was wondering about the meaning of the term "parent_bssid". Given > your remark it means something else than my guess. I actually meant > the distance to the AP indicated by this BSS. Our gscan code obtains > the gscan results from firmware and in that API it has RTT info. Oh, ok. Right, that's unrelated to the parent_bssid. I do wonder how it'd even be possible to *determine* this though? Perhaps by the ACK timing, assuming it's precise on the AP? > However, recent testing revealed those fields are always coming up > with zero values :-( Heh :-) > So right now I am not sure if we need this extension. FWIW, we don't seem to have it. johannes
Re: [RFC V2 1/5] nl80211: allow reporting RTT information in scan results
On 28-11-2016 15:32, Johannes Berg wrote: > >> + * @distance: distance to AP with %parent_bssid in centimeters. Zero >> + * value indicates this is undetermined. >> + * @var_distance: variance of %distance indicating accurracy. > > accuracy > > The distance between the two APs? Where are you even obtaining that > information from? I was wondering about the meaning of the term "parent_bssid". Given your remark it means something else than my guess. I actually meant the distance to the AP indicated by this BSS. Our gscan code obtains the gscan results from firmware and in that API it has RTT info. However, recent testing revealed those fields are always coming up with zero values :-( So right now I am not sure if we need this extension. Regards, Arend
Re: [RFC V2 1/5] nl80211: allow reporting RTT information in scan results
> + * @distance: distance to AP with %parent_bssid in centimeters. Zero > + * value indicates this is undetermined. > + * @var_distance: variance of %distance indicating accurracy. accuracy The distance between the two APs? Where are you even obtaining that information from? johannes
