Process Interface

Process interfaces are used when a process is cut into pieces and the pieces are put into different diagrams. They are put at the end of a preceding part or the start of a subsequent part and serve as navigational aids for opening the respective diagrams. Each process interface gets an assignment pointing to the diagram with the other process part. They are therefore not the elements linking the process parts; the events are. The linking is done by placing an occurrence copy of an event at the end of the preceding process part and at the start of a subsequent process part, just before and after the process interfaces respectively.

The linking of process parts in different diagrams should be the only case where process interfaces are used. They should not be used within the process flow, i.e. directly preceded and followed by an event in the same diagram, because the semantics of such a construct are not clearly defined. Some people use process interfaces like this to indicate the reuse of process parts within the process flow, but as far as I know they were not designed for this. The recommended way for this would be to use a regular function with an EPC as an assignment where the start and end events in the assigned EPC are occurrence copies of the respective events before and after the function on the upper level. Note however that such a construct involves two levels of detail: the original EPC and the assigned EPC which describes the function in the original EPC in more detail. (In contrast, the situation described in the first paragraph above involves only one level of detail.)

The simulation will be able to cope with any of the above-mentioned constructs as long as the process parts or processes detailing functions are connected correctly by using occurrence copies of events, but my suggestion would be not to use process interfaces within the flow due to the reason mentioned above.

I'm not sure what "broken link" refers to in the original post, so I'm not able to comment on that. Hopefully the above explanations help with that nevertheless.