Ports are used to define the interfaces of Processes.
- PortImplementation - at the most detailed level, a PortImplementation defines the specific interface of a process: for example, its expected inputs or produced outputs.
- PortAlias - a PortAlias provides a reference point to some other Port (either another PortAlias or a more detailed PortImplementation).
- PortDelegation - defines the parent-child relationship between Ports: for example, which PortImplementation a particular PortAlias delegates to.
- ProcessPort - defines the Port(s) that are used by a given Process as its interface(s).