Default Diversity Level
If you are designing for two or three configured paths, select the Default Diversity Level to target (site, link, or facility) between the paths in case it has not already been specified on a per-tunnel basis.
Site diversity means that the two paths do not intersect at any given site (besides the source and destination). Link diversity means that the two paths do not intersect at any given link. Site diversity is always stronger than link diversity as site diversity implies link diversity.
SRLG/Facility can be used for SRLG-diversity. In this case, the facilities should be defined before the Path Design. This can be done in Modify mode via the Modify > Elements > SRLG/Facilities window, or by creating a facility file and reading it in via File > Load Network Files in Design mode.