9. Connections and Flows
A connection is a linkage that represents communication of data and control between components.  This can be the transmission of control and data between ports of different threads or between threads and processor or device components.   A connection may denote an event that triggers a mode transition.  The timing of data and control transmission depends on the connection category and on the dispatch protocol of the connected threads.  The flow of data between parameters of subprogram calls within a thread may be specified using connections.  Finally, connections designate access to shared components.
A flow is a logical flow of information through a sequence of threads, processors, devices, and connections. A component can have a flow specification, which specifies whether a component is a flow source, i.e., the flow starts within the component, a flow sink, i.e., the flow ends within the component, or there exists a flow path through the component, i.e., from one of its incoming ports to one of its outgoing ports.