This read-write setting, when enabled, allows a new connection to be added to this channel or port even though doing so would push the interface into an oversubscribed state that would normally be blocked. It's an override for admins who deliberately want to accept the risk of oversubscription, for example when actual traffic is known to run well below contracted rates. An admin needing to add one more low-usage PVC to an interface already flagged as bbIfOversubscribed might enable bbChanOvrSubOvrRide to force the addition through despite the oversubscription check.