[Babel-users] No longer ignoring very bad neighbours

[Juliusz Chroboczek]

Grégoire and Julien have been complaining about Babel ignoring very
lossy links; they claim that links with up to 90% packet loss are
useful.  (Note that Babel measures packet loss *before* link-level ARQ
is applied, so that's not the amount of packet loss you will see if
you simply ping a neighbour.)

I've just changed the link cost computation on wireless links so that
it will consider neighbours even when they loose no more than 11
hellos.  This should not change Babel's behaviour when better links
are available, but will prevent Babel from discarding links that
disappear in a timely manner, which might potentially cause blackholes
in some very unlikely topologies.  Let me know if you see any new
issues.

I've installed the new version on alpha and beta; Julien, could you
please copy it over to gamma, which I cannot access right now?

                                        Juliusz