Dr. T: A Communications Infrastructure for Distributed Interactive Applications

Dr. T is a simple communications infrastructure designed to support distributed interactive applications such as networked games, chat programs, and shared whiteboard systems. It hides from application programmers the details of networking software and presents a very simple abstraction of distributed process group input: each process receives the same stream of interleaved keystrokes from the members of the group. Dr. T attempts to supply inputs to process group members frequently enough to keep pace with a 30 Hz screen refresh rate. This paper describes the design of Dr. T, presents a simple implementation of the concept, and illustrates the system with a sample "game" application. Timing tests show that Dr. T performs well on local area networks for groups of more than 30 processes. Calculations based on careful measurements of network performance suggest that more sophisticated implementations of Dr. T can scale to over 100 processes. This paper is available in HTML on the Web at ..