[Babel-users] Should I use wifi mesh routing in crisis situations?

[Juliusz Chroboczek]

Hi Valent,

> my name is Valent and I'm founder of www.otvorenamreza.org which is a
> partner project with Wlan Slovenia (we are neighbours) and also
> www.meshpoint.me

We know.  You're famous :-)

> We currently have mostly single radio nodes (tplink wr841nd and
> ubiquiti nanostation Loco m2) in our network and by default all of our
> nodes also run mesh on same radio but via adhoc interface.

> In my short experimentation this showed to work quite poorly, even
> with two nodes separated by only 10 meters on top of two building this
> mostly failed to work and we had lots of connectivity issues. Once I
> switched these two nodes to ap and sta modes link was rock solid.

Yes, that kind of setup tends to suck.  There are two issues with your setup:

  1. ad-hoc mode doesn't work as well as infrastructure mode;
  2. using the same frequency for transit and client access reduces througput.

For (1), the best solution is to set up a bunch of point-to-multipoint
links using AP/STA mode.  If you're using diversity routing (Babel-Z), be
aware that current versions of babeld are unable to automatically
determine the channel number of interfaces in AP mode -- you'll need to
set them manually.

For (2), the best solution is to use multiple radio frequencies.  If you
have two frequencies, use one for client access and one for transit.  If
you have multiple radio frequencies, set all but one of them for transit,
and let Babel-Z choose the frequencies.

If multi-radio routers are too expensive for you, Babel-Z is able to work
with the "JBOL" topology: a bunch of single-radio routers, all connected
to the same Ethernet switch (possibly internal to one of the routers).  If
the channel numbers are set up correctly, Babel-Z should be able to
distribute traffic across multiple frequencies in that configuration.

Please let us know about your results,

-- Juliusz