Explanation of iwconfig output?

SlowCoder · 05-20-2009, 06:44 PM

I'm just looking for some clarification on the readings from iwconfig.

Take the following:

Code:

$ iwconfig wlan0
wlan0     IEEE 802.11  Nickname:""
          Access Point: Not-Associated   
          Link Quality:5  Signal level:200  Noise level:166
          Rx invalid nwid:0  invalid crypt:0  invalid misc:0

$ man iwconfig
...
Link quality - Overall  quality  of  the  link.  May  be  based on the level of contention or interference, the bit or frame error rate, how good the received signal is, some timing synchronisation, or other hardware metric. This is an aggregate value,  and  depends  totally  on  the driver and hardware.

Signal level - Received signal strength (RSSI - how strong the received signal is). May be arbitrary units or dBm, iwconfig uses driver meta information to interpret the raw value given by /proc/net/wireless and display the proper unit or maximum value (using 8 bit arithmetic).  In Ad-Hoc mode, this may be undefined and you should use iwspy.

Noise level - Background noise level (when no packet is transmitted). Similar comments as for Signal level.
...

Am I to take that signal and noise levels are calculated the same? Are the levels indicated above normal or abnormal?

Noticing that the value of Link quality is 5, I'm used to seeing a value over another value (e.g. 60/100 or 30/60). Can this be explained? Is there a maximum value?

How can I use these values to determine the total quality of my connection?

baldy3105 · 05-21-2009, 04:19 AM

The help says that the value "depends totally on the driver and hardware" i.e iwconfig is simply reporting what the driver tells it.

So you need to find out what driver your wireless card is using and then you'll need to google specifically for it to find out what these numbers relate to.