This indicates the specific mode used to enforce path diversification for this tunnel, working together with the path disjoint type to determine how strictly the disjointness requirement is applied during path computation. An admin checks this alongside the disjoint type value to fully understand the actual diversity guarantee in effect for this specific tunnel's backup path selection. For example, a stricter mode setting might cause path computation to fail outright if no fully disjoint path exists, rather than falling back to a partially-overlapping route.