Figure PR.25 - Relating PhysicalPorts to Cards and Chassis

PhysicalPorts can be placed on either a Card or a Chassis. Thus, we end up with the following Figure.<br/>Note that the EquipmentInHolder relationship enables a LineCard to be attached to a Slot. We made two distinct relationships to model the containment of Ports (PortsOnCard and PortsOnChassis) because the common superclass of LineCard and Chassis is Hardware. If we had run a relationship between Hardware and PhysicalPort, then PhysicalPorts could contain PhysicalPorts, which is not correct. In addition, this differentiation will help us in the System view, since the semantics of a PhysicalPort on a Chassis are different than those of a PhysicalPort on a Card.<br/>