A reference to an external port within a different Product Flow Model. This value represents a foreign key from one element to another. A pointer to the external port in the network that represents the current Model. This is the port to which a different model is being connected. A pointer to the external port within the connected Model. This is the port on a different model to which the port on this model is connected. A pointer to the Product Flow Model that contains the connected port. The name of the facility that is represented by the connected model. The name can be qualified by a naming system. This also defines the kind of facility. The unique identifier of the recurring element.