Enabling disjoint backup paths for FRR detours and bypass SRLG disjoint configuration

About this task

The following details the steps necessary to create shared risk link groups for FRR detours/bypass SRLG disjoint configuration.

Create an SRLG group, similar to admin groups.
Link the SRLG group to MPLS interfaces.
Enable the srlg-frr (strict/non-strict) option, which is a system-wide parameter, and it forces every LSP path CSPF calculation, to take the configured SRLG memberships (and propagated through the IGP opaque-te-database) into account.
Configure primary FRR (one-to-one/facility) LSP paths. Consider that each PLR will create a detour/bypass that will only avoid the SRLG memberships configured on the primary LSP path egress interface. In a one-to-one case, detour-detour merging is out of the control of the PLR, therefore the latter will not ensure that its detour will be prohibited to merge with a colliding one. For facility bypass, with the presence of several bypass types to bind to, the following priority rules will be followed:
1. manual bypass disjoint
2. manual bypass non-disjoint (eligible only if srlg-frr is non-strict)
3. dynamic disjoint
4. dynamic non-disjoint (eligible only if srlg-frr is non-strict)