[Babel-users] Plans for incompatible changes

[Juliusz Chroboczek]

Dear all,

Here, at Babel Towers, we've been taking backwards compatibility very
seriously.  While we have regularly made incompatible changes to the
configuration file format, we've kept the wire format backwards compatible
since babeld 0.90, released in September 2008.

I am sorry to say that we're planning to make some incompatible changes to
the source-specific extension in 1.9.0.  Precisely:

  - the core Babel protocol will remain unchanged;
  - both the RTT routing and the diversity routing extensions will remain
    unchanged;
  - the source-specific routing will use a completely new packet format.

What that means for you is that:

  - if you are not doing any source-specific routing (and if you don't
    know what that means, you probably aren't), you will not be impacted;
  - if you are doing source-specific routing, new and old implementations
    will still exchange non-specific routes, but they will silently ignore
    each others' source-specific routes, which might cause blackholes.

Sorry for that, but the redesign will make for a cleaner and more compact
protocol.  Please let us know if that is unacceptable for you, and we'll
bake you a transitional version that speaks both versions of the protocol.

-- Juliusz