[j-nsp] Use IGP metrics for BGP routes

[Aaron Gould]

Rolf, If what I was dealing with recently is the same as what you are asking
about, you are looking for "set protocols ldp track-igp-metric"

When I learn multiple same routes from mpls l3vpn pe's, the router id was
the tie breaker... this was annoying and unacceptable to me since the lowest
router id was further away in some cases.

show route 0/0 exact table fourfour.inet.0 | grep "reason|metric"

Bgp best path selection does use IGP as part of its algorithm, but, when
using mpls l3vpn, bgp uses inet.3 metric as that igp metric.... guess what
is in inet.3 by default ?  metric 1 for all prefixes 

show route table inet.3 terse

but...the igp metric you desire for bgp to use in this case is in inet.0

show route table inet.0 terse

now do this...

set protocols ldp track-igp-metric
commit

this will copy the real igp metric from inet.0 into inet.3.... as I
understand that command, that's all it does.  Magic.

show route 0/0 exact table fourfour.inet.0 | grep "reason|metric"

This was a heard thing for me to find... but someone on the internet in
juniper forum mentioned it, and that's what solved my problem.

https://forums.juniper.net/t5/Routing/Multipath-in-vrf-routing-options/td-p/
295368

- Aaron