[Babel-users] Diversity routing in a many channeled world

Dave Taht dave.taht at gmail.com
Wed Jun 17 23:20:07 UTC 2015

On Wed, Jun 17, 2015 at 3:38 PM, Juliusz Chroboczek
<jch at pps.univ-paris-diderot.fr> wrote:
>> To somewhat answer my own question, when babel is used on a standalone
>> "AP" interface, it is unable to automagically determine the channel it is
>> on. So I guess whatever it uses can only figure out a adhoc interface?
> The message you're getting means that the SICGIWFREQ ioctl has failed.
> Could you please ask the netdev mailing list whether it's supposed to
> succeed on an AP, and whether I should be using a different API?

well, linux-wireless would be better and for sanity's sake I am
currently on neither list.

So I went to a definitive bit of source code instead:

apt-get source network-manager

This has a truly mindblowing level number of abstractions piled on

and what I see in src/wifi are libs for wext and nl80211.

for wext, I see SIOCSIWFREQ being used, only, in network-manager.  I
have no idea what the two differ in actual intent?

#define SIOCSIWFREQ     0x8B04          /* set channel/frequency (Hz) */
#define SIOCGIWFREQ     0x8B05          /* get channel/frequency (Hz) */

nl80211 has this rather big dump format, but seems comprehensive.

I would suspect nl80211 is more of what is needed nowadays... (this is
an ath9k chip here)... or all 3.

sort of on this topic was being able to distinguish between ht20,
ht40, and the newer vht80, 160, 320 modes, which babel supports
multiple channels in the encoding, but I am not sure is pulled out in
the code. And on 2.4ghz channel 3 interferes with both 1 and 6. Etc.

on to babel-1.6.2! :)

> -- Juliusz

Dave Täht
worldwide bufferbloat report:
What will it take to vastly improve wifi for everyone?

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