802.11N confusion

[Dan Ritter]

On Mon, Mar 08, 2010 at 03:42:28AM -0500, Tom Metro wrote:
> I was disappointed to see that the common WiFi scanning tools for Linux 
> wouldn't report the channel that a discovered network was on. (I know 
> the war driving tools, like Kismet, report this, but it shouldn't be 
> necessary to use something that specialized just to look for the least 
> crowded channels.)

The standard wireless tools will tell you:


dsr at dryad:~$ /sbin/iwlist ath0 scan
ath0      Scan completed :
          Cell 01 - Address: 00:18:01:F5:DF:47
                    ESSID:"S6534"
                    Mode:Master
                    Frequency:2.412 GHz (Channel 1)
                    Quality=8/70  Signal level=-87 dBm  Noise level=-95 dBm
                    Encryption key:on
                    Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 6 Mb/s 9 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 54 Mb/s
                    Extra:bcn_int=100
                    Extra:wme_ie=dd180050f2020101020003a4000027a4000042435e0062322f00
          Cell 02 - Address: 00:1D:7E:DF:26:E8
                    ESSID:"linksys"
                    Mode:Master
                    Frequency:2.437 GHz (Channel 6)
                    Quality=14/70  Signal level=-81 dBm  Noise level=-95 dBm
                    Encryption key:off
                    Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 18 Mb/s 24 Mb/s; 36 Mb/s; 54 Mb/s; 6 Mb/s; 9 Mb/s 12 Mb/s; 48 Mb/s
                    Extra:bcn_int=100


Look at the line marked Frequency, followed by Channel.

> Similarly there was no apparent way to determine what 802.11 standard 
> was being employed by your wireless connection in Ubuntu, other than 
> inferring it from the reported connection speed.

You can set this, via 'iwconfig $IFACE modulation $TYPE', but
it's true that most WIC drivers do not make that info available.

dsr at dryad:~$ /sbin/iwlist ath0 modulation
ath0      unknown modulation information.

-dsr-

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