[Babel-users] fun with babeld, and tools for measuring ETX for Babel meshes

[Michael Richardson]

Hi,
Today was Canada Day, and I spent the morning in the basement flashing the
latest CeroWRT on the set of NetGear 3800s that I bought back in March of
2013. (My, how time flies)

My plan has been to setup a community mesh network as an experiment, to try
Babel on it, and later on try out RPL.   (I could also play with HNCP, but
that's intentionally not supposed to be community oriented: with an "AS")
Some time ago, I created a map with 300m circles from my home, wondering if
I could make it as far as my nearest relatively geeky friend on Tweedsmuir
Avenue.   I was pretty sure that I couldn't do it in one hop; and my circles
were to figure out which of my neighbours in between I might persuade to let
me plug a 3800 in; we can try solar powered ones afterwards.
For now, I'm thinking about second floor windows, indoors.

Anyway, at 3:30pm (and several dips in the pool... it's 40C today) I was
ready to head out, and my assistant and I went out around the block.  Please
see picture gallery at:
  https://plus.google.com/photos/103865510556691933694/albums/6031203377916425729?authkey=CJSkqIOWkJ3t8QE

My ASUS tablet (with a debian chroot) was told to join my "mesh43" node,
which was plugged into the APC UPS (with a newly refurb battery).  My mesh55
node was in an upstairs window at my house, connected to my primary 3800
that is the basement lab where the computers, switches and DSL modems, etc. are.
I get rather poor 5Ghz coverage in my house from that location, and my plan
is to eventually make the mesh55 node permanently fixed in the attic, cabled
by wired network and wired power up a utility wall.

Anyway, we went around the block, and up a street named Belford, which took
us within 60m of my friend on Tweedsmuir.  My assistant was instructed to
read me the packet loss rates, and whenever he thought it was interesting,
to push the screen capture button.  I realized later that mtr -t doesn't
default to showing Snt/Rcv and loss in -t mode, and so actually the loss%
is very cumulative, and so our numbers are much less meaningful.

If someone knew of a native Android app that would do a traceroute and/or
ping, and log the results to a KMP file that would be ideal.  Looking around,
lots of war driving programs, but I don't care about the wifi signal that the
tablet (which hasn't got 802.11a or 802.11n) gets, it's the 3800 I care about.

The 3800 has two radios: and b,g,n radio, and 802.11a radio.  I think of
it as the 2.4Ghz radio and the 5Ghz radio, but my understanding is that
802.11n uses both 2.4Ghz and 5Ghz.  The 3800 doesn't have external antenna;
and so I agree that it's not the best device for this, but it runs cerowrt,
and that's what's important.

One thing you can see in the screen shots is that at a certain point (slide
11 of above) the intermediate hop is no longer :82::1 (which is the 5Ghz
interface) to the :8f::1 (the 2.4Ghz radio).  I find mtr unclear when/if it
switches back.

The best would be to get the RX power right from the radio.
Does babel currently get any info that way?  I think that
mac80211/etc. framework now has that kind of thing now.

In the ROLL/RPL/contiki space, I have been considering a NETCONF/YANG
way to get the mesh adjacencies (in particular, knowing the one which were
not chosen by each node) via a CoAP interface.  Such a thing could also be
used for Babel.

Google turned most of the screen shots into an animated PNG, which is amusing:
  https://plus.google.com/u/0/photos/+MichaelRichardson/albums/6031203377916425729/6031248078749875762?authkey=CJSkqIOWkJ3t8QE&pid=6031248078749875762&oid=103865510556691933694

I think we will go out again tomorrow morning and see if we can do this
again, and he'll be instructed to use the "R" key to restart the statistics.

--
]               Never tell me the odds!                 | ipv6 mesh networks [
]   Michael Richardson, Sandelman Software Works        | network architect  [
]     mcr at sandelman.ca  http://www.sandelman.ca/        |   ruby on rails    [

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