> for pcap captures with Radiotap headers, it's radiotap.dbm.antsignal,
>shown as dBm.
After few captures It seems to be: (IEEE802.11 RSSI) =
(radiotap.dbm.antnoise) - (radiotap.dbm.antsignal)
I'm using Wireshark 1.0.0
(1.2.0 is not in my repository) and modified MadWiFi drivers for 802.11p.
Do
you know any difference about how 1.0.0version and 1.2.0version capture data?
I'm going to do some test in 802.11p communication capturing data in several
hosts using 1.0.0 and analyzing data using 1.2.0. I hope there is no
difference! If there are some let me know and I'll spend few hours changing
all...
thanks
Davide
>> and a custom colums radiotap.dbm.antsignal
>> I'm
very surprise
>> to see different values for those columns
>
>Given that the
Radiotap code, at least in the top-of-tree version of
>Wireshark just puts up
the radiotap.dbm.antsignal value, I'd be
>*extremely* susprised to see
different values.
>
>The 1.2.0 code should behave the same as the top-of-SVN-
tree version;
>what version of Wireshark are you using?
>>
>
>----
Messaggio originale----
>Da: guy@xxxxxxxxxxxx
>Data: 26/06/2009 22.25
>A:
"iodavide@xxxxxxxxx"<iodavide@xxxxxxxxx>, "Community support list for Wireshark"
<wireshark-users@xxxxxxxxxxxxx>
>Ogg: Re: [Wireshark-users] radiotap RSSI v.s.
IEEE802.11 RSSI
>
>
>On Jun 26, 2009, at 7:42 AM, iodavide@xxxxxxxxx wrote:
>
>> I'm using Atheros device and I'm capturing data from monitor interface
>>
using Radiotap
>> To better understand link quality I've selected two columns:
>> IEEE 802.11 RSSI
>
>At least as I read IEEE 802.11-2007, RSSI is just some
positive number
>such that
>
> 1) it's between 0 and some maximum;
>
> 2) the
greater the value, the more power is being received at the
>antenna;
>
>with
no indication of what it means other than that.
>
>What Wireshark displays in
the "RSSI" column depends on the type of
>capture; at least in the top-of-SVN-
tree version:
>
> for captures from AiroPeek, it's a percentage -
RSSI/max_RSSI*100 (as
>that's what AiroPeek saves to the file, at least as I
read one of
>WildPackets' documents);
>
> for captures from CommView, it's a
percentage - probably the same as
>AiroPeek, but I didn't find anything
obvious in their document to
>indicate what it is;
>
> for captures from
Windows Sniffer, I *suspect* it's a percentage,
>probably the same as
AiroPeek;
>
> for captures from Shomiti's wireless version of Surveyor (Finisar
no
>longer seem to offer it), I don't know what it is;
>
> for pcap captures
with Prism headers, it's whatever the heck the
>particular driver puts there
- a quick look at the drivers didn't
>indicate that they put anything there;
>
> for pcap captures with AVS headers, it's signal strength as either:
>
>
"Normalized RSSI" - integers in the range [0-1000] where higher
>numbers
indicate stronger signal, with no particular mapping to an
>actual signal
strength;
>
> dBm - an actual received signal strength, in dBm;
>
> a raw
RSSI value, which is probably the raw IEEE RSSI value;
>
> with the column
indicating which it is;
>
> for pcap captures with Radiotap headers, it's
radiotap.dbm.antsignal,
>shown as dBm.
>
>
>> and a custom colums radiotap.
dbm.antsignal
>> I'm very surprise
>> to see different values for those columns
>
>Given that the Radiotap code, at least in the top-of-tree version of
>Wireshark just puts up the radiotap.dbm.antsignal value, I'd be
>*extremely*
susprised to see different values.
>
>The 1.2.0 code should behave the same as
the top-of-SVN-tree version;
>what version of Wireshark are you using?
>>
>
