The picture on the previous slide captures the static relationships between the various components, but does nothing to indicate the dynamic flow of messages during the processing of a senario. To capture this information a different type of diagram can be used.
This chart is called an interaction diagram. Is is read from top to bottom. Each component is marked by a vertical line. Communication between components is marked by horizontal directed arrows between the vertical lines. A comment on the far right then indicates the nature of the connection.