[Battlemesh] Metrics [was: Session about multi-homed IPv6 mesh networks and auto-configuration]

[Juliusz Chroboczek]

> My point is that in order to take an informed decision about which exit
> link to use we need _something_ that correlates to how 'good' the exit
> link is.

It looks we're in full agreement, except that I don't think it's specific
to exit links -- it's also important to choosing paths within the routing
domain (the "mesh").

Both Henning (in OLSRv2) and myself (in Babel) have done some serious work
about plug-and-play metrics for our respective routing protocols.  You'll
find Henning's work here:

  https://tools.ietf.org/html/draft-ietf-manet-olsrv2-dat-metric-12

As to Babel, the metric used by default in Babel is defined in Appendix
A of RFC 6126.  Babel, like OLSRv2, supports alternative metrics, and the
most mature one is the one that's designed for tunnels:

  http://arxiv.org/pdf/1403.3488

There's some other work on metric in Babel, notably the metric described
in draft-chroboczek-babel-diversity-routing.

There's a lot of work to be done on refining our metrics and defining new
ones.  I'm definitely interested to hear suggestions and to help people
experiment with new ideas.

-- Juliusz