[c-nsp] LDPv6 Census Check

[Robert Raszuk]

> Seems weird, because neither LDP or SR implies globally significant
> labels, implementation choice. What SR does imply is a continuous
> block of labels of equal size in domain.
>

LDP or MPLS LSPs require hop by hop label swapping (directly connected or
over say IP tunnels). So labels in LDP are always locally significant.

SR-MPLS implies globally (domain wide) label significance. Index in the IGP
extensions is there just to relax requirement to use the same block on all
nodes - so the block does not need to be continuous in an SR domain. It is
recommended by Cisco but not required by standard.

Thx
R.