The only processes that communicate with each other between nodes in a cluster are the Process Managers and the SWDIR\
util\
swsvrmgr process. The
swsvrmgr process tells the process managers what actions to perform. They communicate via the TIBCO iProcess Engine event mechanism by publishing and subscribing to events.
For example when you start the system by running SWDIR\
bin\
swstart, the swsvrmgr START utility publishes an event to say that the system needs to start up something. All the process managers on all the nodes in the cluster should receive that event and start up any processes that are configured to run on that node. Similarly on shutdown, a shutdown event is published and each machine's process manager should receive the event and shutdown any appropriate processes.