How is wireless signal strength for NetworkManager calculated

[Matthew Saltzman]

On Sun, 2014-01-19 at 22:58 -0600, Ranjan Maitra wrote: 
> Hi,
> 
> I was wondering how wireless signal strength (as displayed by the
> network-manager applet) is calculated. There is a percentage reported:
> what does this percent mean and where does NetworkManager get its
> values from?

Not sure if this is still relevant, but it was part of the early
development of NetworkManager, developed right down the hall from me.

http://www.ces.clemson.edu/linux/nm-ipw2200.shtml


> 
> While I am  here, I also wanted to know the answer to the question as
> to how the interfaces are decided in latter-day Fedoras: to elucidate,
> it used to be that eth0 and wlan0 and ppp0 were the interfaces. Now it
> seems to depend (and vary from one machine to the other). How do these
> get decided nowadays? Is there a generic way to get to the correct
> interface to use in programming? I am thinking of conky which requires
> the interface (from ifconfig, say) to set up signal strength, etc.
> 
> Many thanks for any enlightenment and best wishes,
> Ranjan
> 

-- 
Matthew Saltzman
Clemson University Math Sciences
mjs AT clemson DOT edu