The network data delivery service: real-time data connectivity for distributed control applications

The network data delivery service (NDDS) is a novel network data-sharing system. NDDS builds on the model of information producers (sources) and consumers (sinks). Producers generate data at their own discretion, unaware of prospective consumers. Consumers “subscribe” to data-updates without concern for who is producing them. The routing protocol is connectionless and nearly “stateless”, thus network reconfigurations, node failures, etc. are handled naturally. This scheme is particularly effective in systems (such as distributed control systems) where information is of a repetitive nature. NDDS provides support for multiple producers, reliable data-delivery, consumer update guarantees, notifications vs. polling for updates, dynamic binding of producers and consumers, distributed queries, and user-defined data types. NDDS is integrated into the ControlShell real-time framework and is being used in several robotic applications as an effective means of information sharing between sensor systems, robot controllers, planners, graphical user interfaces, and simulators