Pending bird patches and discussions for proto/babel

[Daniel Gröber]

Hello birds,

I just thought I'd put together an overview of as yet unresolved
proto/babel patches and discussions to stimulate some activity :)

Toke's RTT series:

- lib/timer: Add current_time_now() function for immediate timestamp
- babel: Add support for the RTT extension
- babel: Add route metric smoothing

My route selection revamp:

- [v5] Babel: Replace internal route selection by bird's nest
- [DRAFT] Babel: Implement route daming with fixed delay    (s/daming/damping/)

Toke's first two patches are ready for merging, but the third (metric
smoothing) is contested since it conflicts with my route selection patch in
its current form and if adapted it conflicts with my scalability goals for
babel instead. Possibly premature optimization admittedly ;)

Initially Toke was playing with the idea of exposing the smoothed metric to
route filters in a followup patch. Me and Juliusz oppose this, for
different reasons and the consensus is to not do that.

My stance is that we could choose to merge smoothing as long as we don't
expose it's implementation internals (the smoothed metric) to users. This
way we can replace it with a more performant approach later.

That being said since RTT metric is a new feature anyway I would prefer we
just go with my route damping approach, mark RTT as experimental and get
some more wider testing through a released version.

Lastly my v5 route selection patch should also be ready, all threads of
discussion should be resolved and there are no known bugs. However I've not
received any testing reports, hint, hint peeps °>°

--Daniel