The remaining problem is the
relation between node protecting and link protecting inequality. Please read
the following words:
As for node-protecting alternatives,
I read the following description in section 3.3. Broadcast and
the shortest path from the pseudo-node goes through E, if a
from a neighbor N is node-protecting, the
alternate will also be
link-protecting unless the router S can only
reach the alternate
neighbor N via the same pseudo-node."
This means only the SRLG of
broadcast and NBMA links make the node-protecting LFA failed to provide link
protection. Except for this, node-protecting alternate should always be link
protecting. Is that right?