[Babel-users] link costs

Juliusz Chroboczek Juliusz.Chroboczek at pps.jussieu.fr
Tue Jan 6 19:40:36 UTC 2009

> a) There are many cases where the automatic detection if an interface is
> wireless fails. [...] having some way to do this on an per interface
> basis would be nice.

Yes, although if Babel is mis-detecting, then you're probably doing
something wrong, such as running Babel over tunnels over wireless (which
breaks ETX computation).

> b) Currently the default costs 96 for wired links and 256 for ETX=1 links
> are hardcoded into the program. In practice I want to set these costs on
> a per interface basis too:

Yes, although as you justly note, in most cases you can get away with route

But I fully agree with you that we need some facilities for per-interface
configuration.  The issue is designing a suitable user interface; I think
I've been pretty good at keeping the babel.conf syntax simple and regular,
and I'd like to keep it this way.

I'm currently thinking of something like

  interface eth* wireless no cost 128

The keyword ``interface'' is followed with a shell regexp, which specifies
which interfaces this clause applies to.  The rest is a sequence of
keyword/value pairs.

What are the per-interface properties we need?  I'm thinking of


Anything else?


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