This read-write TruthValue object marks the associated preferred route (set via vismChanPrefRouteId) as a directed route, meaning it's the only permitted route for the connection, and the connection fails outright if that preferred route becomes unavailable; it's not applicable if no preferred route is associated. This is a strict routing constraint with real availability risk, since enabling it removes PXM's ability to fail over to any alternate path. An engineer with a regulatory or security requirement that traffic travel only over one specific approved path would enable this object, accepting that the connection will drop entirely if that path fails rather than rerouting.