Distribution ports are defined by IfcDistributionPort and attached by the IfcRelNests relationship. Ports can be distinguished by the IfcDistributionPort attributes Name, PredefinedType, and FlowDirection ModelView for mvdXML 1.1 documentation.> Simple example for checking sensor elements to always submit signals. Concept to validate that every sensor element has a port defined that submits signals Concept to validate that every sensor has a port defined that submits signals.