metric 0 vs 'no metric at all'

[Alexander Koch <efraim () clues de>]

Hiya,

I was wondering if someone had done any or some research on
this before... basically I am not sure with all the many
implementations of BGP and all the vendors if and what those
will do when they see a metric of 0 and no metric. I am not
an expert knowing the actual protocol's messages exchanged,
but I see some routes with nothing in the metric field on
the various show commands, and some have explicit '0' metric.

I do not trust all the BGP implementations around, and we
consider changing the default outbound, with MEDs of course
still available on request.

Alexander