An international high-speed packet-switching experiment

The performance of a communications processor in high speed digital satellite circuits has been field tested by means of a data link between Clarksburg, MD, and Oberpfaffenhofen, West Germany. The two communications processors were connected via 1.544-Mbit/s links provided by rooftop earth terminals, and 14/11-GHz spot beam transponders in an Atlantic Ocean region Intelsat V spacecraft. The results obtained indicate that such integrated services as simultaneous freeze-frame teleconferencing, high speed host file transfers, facsimile, and low speed asynchronous terminal and host communications, are possible. Attention is given to the effect of data communications protocols on throughput efficiency and overall network performance, as well as to the devising of a hybrid multiplexing scheme which allows both stream and packet traffic to share a common channel.