DataFlow is designed to permit embedding inside of a larger application. Sometimes it is necessary to integrate a dataflow graph with code residing outside of the graph. This code either feeds or consumes (or possibly both) data into the graph.

An external port is similar to a port on an operator, but instead is on a graph. External ports are used the same way as an operator port. The difference is that the code embedding and executing the graph is responsible for reading and writing data on the port.

You should be aware of a few issues with external ports. Using External Ports provides more information on declaring and using external ports.