This counter reports how many one-to-one-backup detour LSPs are currently leaving this device, a count that is only meaningful when oneToOneBackup mode is active since it is defined to read 0 under facilityBackup. Because the value collapses to 0 whenever the router is actually running facility backup instead, an admin must already know which FRR mode is configured or a 0 reading is ambiguous between 'no protection' and 'protection via bypass tunnels, wrong counter.' For example, a PLR protecting 40 primary LSPs in one-to-one mode might show 40 detours leaving it, while the same router switched to facility backup would always read 0 here regardless of how many bypass tunnels exist.