Despite being described as a bitmap, this is exposed as a simple choice indicating whether this ATM circuit's user data plane is configured as point-to-point or supports point-to-multipoint delivery, which determines whether the circuit can fan traffic out to multiple destinations the way cktMcastGroupId circuits do at the Frame Relay layer. An admin setting up an ATM-layer broadcast application would set this to point-to-multipoint(2) rather than leaving it at the point-to-point(1) default used by most ordinary circuits.