This read-write value, per its NsSourcePriority syntax, sets the priority ranking of this candidate timing source relative to other candidates. An admin sets it to control which candidate source the device prefers to lock to when multiple valid sources are available. For example, an admin would assign the primary reference clock the highest priority and a backup source a lower priority, so the device only falls back to the backup if the primary fails (illustrative, since the source MIB has no DESCRIPTION text).