Node protection support in TI-LFA and remote LFA

This feature extends the Remote LFA and TI-LFA features by adding support for node protection. The extensions are additions to the original link-protect LFA SPF algorithm.

When node protection is enabled, the router prefers a node-protect over a link-protect repair tunnel for a prefix if both are found in the Remote LFA or TI-LFA SPF computations. This feature protects against the failure of a downstream node in the path of the prefix of a node SID except for the node owner of the node SID.