1. An HVAC data processing and communication network, comprising: an active subnet controller configured to act as a network controller; an inactive subnet controller configured to back up parameters stored in said active controller and to act as the network controller when said active controller malfunctions; a user interface configured to publish a privilege request message to a data bus; a system device configured to: receive messages via said data bus; store configuration data in nonvolatile memory; enable a privileged operating mode not normally available to a user of said network in response to said privilege request message; and wherein said active subnet controller is selected by a negotiation process based on a set of features and parameters of each subnet controller by entering a startup state upon power-up.