[Babel-users] IPv4: Default Route stability

[Juliusz Chroboczek]

> How stable is default route selection here? Since NAT-Sessions break
> when using a different default route, a certain stability would be great.

Hysteresis is applied to route selection.  The amount of hysteresis is
controlled with the parameter smoothing-half-life (-M), 4s by default.
Increase this parameter to have higher stability at the cost of slower
convergence.

> Can I configure a threshold t, so that babel does not use a better
> default route, unless the costs differ by t at least?

No, babeld will eventually converge to the best route.  All you can do is
slow down convergence so it switches less often.

Another solution is to use source-specific routing to solve the problem
completely, but that's probably more work than you're willing to put into
it.

-- Juliusz