This is the relative name of one recorded FSM run entry for a physical FC port, the short identifier distinguishing this particular logged workflow instance from other FSM history entries for the same port. Since a port can have several FSM run records over time (one per config change attempt), the RN is how UCS Manager enumerates and orders that history when an admin reviews what has been done to a port. For example, the RN might encode a sequence number so an admin can tell this is the second recorded FSM run for that port, not the first or most recent.