This DN uniquely addresses an 'affected class' record, which lists a specific managed-object class that a given fault or fault rule is defined to potentially impact. UCS's fault framework defines, per fault type, which classes of managed object can be flagged by it, so an admin building custom fault-suppression or correlation rules references this record to know which object class a particular fault definition actually applies to. A value like sys/fault-policy-msg/affected-class-fabricVlan would identify the fabricVlan class being registered as potentially affected by that fault rule.