A Business Process Modeling Notation (BPMN) diagram shows the interaction between a customer and a pizza shop. The customer and pizza shop vendors have been classified differently. After ordering the pizza, the customer process gets into the event-based gateway: either the pizza is received, or after 60 minutes, he will call the restaurant to know when the pizza will arrive. Meanwhile, when you order a pizza by phone, you decide what you want, order, then wait. With the event gateway, you will receive your pizza within one hour or call back to know what is up after one hour. It should be noted here that there is no default semantics for this type of process modeling, which means one can model collaboration diagrams to show the interaction between business partners. Also, focus on one company, modeling the interaction between departments, teams, or even single workers, and software systems in collaboration diagrams.
