R1

R1 / 1:M

Bank defines service features of one or many Shaft

Shaft has service features defined by exactly one Bank

All Shafts in a Bank provide the same type of service. This includes access to the same Floors and consistent Door behavior. If you want a certain Shaft to skip Floor 3, let’s say, then you would establish a Bank that excludes that Floor and then assign the Shaft to that Bank.

A Bank has no utility if it does not define policy for at least one Shaft.

Since we don’t want two conflicting sets of policies defined for a Shaft, the Shaft must belong to exactly one Bank.