[Babel-users] [B.A.T.M.A.N.] WBMv3: a Babel perspective

Juliusz Chroboczek jch at pps.jussieu.fr
Sat Jun 12 12:04:02 UTC 2010


[Followups restricted to just olsr-users and babel-users.]

>> (1) when the network is broken, Babel is the first to collapse;
>> (2) Babel behaves well when the network is usable;

> Could you be a bit more specific with "usable"?? What does that mean
> regarding packetloss?

If you look at Elektra's writeup, in the first test none of the
protocols achieved more than 18% success -- and that's *after*
link-layer ARQ.  In the second test the figure was 27%.

In the third test, everyone achieved around 75% (after ARQ), which
I think is still pretty marginal, but starts becoming usable.

Perhaps Henning or Elektra can tell us what was the ETX (or,
equivalently, pre-ARQ packet loss) of the productive links in those
tests.

>> (3) Babel generates too many small packets on broken networks.

> Which creates more collisions in the air I assume ;-)

Well, it's still just 30 packets/s (as measured, all nodes added up),
which is well within what 802.11 is designed to handle.  (See Elektra's
slide number 8.)

> yeah ;-) Wish I had been there..

So do I.

                                        Juliusz



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