What defines a bidirectional terminal configuration?

A bidirectional terminal configuration is defined by the absence of distinct upstream or downstream flow. In this configuration, the flow of utilities can occur in both directions without a clear distinction between inputs and outputs.

This allows for greater flexibility in utility networks, enabling features to interact more dynamically. For instance, a pipe or a junction that permits flow to alternate between supplying and receiving fluid does not enforce a strict directional flow. This characteristic is particularly useful in scenarios where the utility network needs to accommodate changes in demand or supply.

The other choices describe aspects that do not align with the concept of a bidirectional terminal configuration. A distinct upstream and downstream flow would imply a clear directionality, contradicting the principle of bidirectionality. A configuration that only allows flow in one direction is inherently unidirectional. Features with varying physical ports could exist in both bidirectional and unidirectional configurations; however, the defining aspect of whether a terminal is bidirectional revolves around the flows themselves, not the physical characteristics.