A central NodeHandler process communicates with NodeAgents, one on each active node in the testbed. The NodeHandler is hosted on one of the testbed's utility servers. Applications are loaded and executed by a NodeAgent on instructions from the NodeHandler. These instructions will also include the initial property settings for the applications.
Communication between the NodeHandler and each of its NodeAgents uses the Control Internet port. Default settings leave the Data Internet port unconfigured and require the experimenter to specifically configure it through the NodeHandler.