Network Design for a Large Class of Teleconferencing Systems

This paper introduces a new class of network design problems implementing an integrated teleconferencing environment consisting of a video space showing images of the participants, an audio space providing their voices, and a graphics space providing reference and discussion material for the conference. These various spaces provide services of differing quality and type. The problem posed is to design topologically optimal networks that are least costly and that will have the flexibility to carry conferences of differing service quality and type. The actual networks studied in this paper consist of the design of a private network for a single conference among identical, but arbitrarily located, sites. Network designs will be minimum link-cost or constrained minimum link-cost optimal, where the first is minimal over all possible network topologies and the second is constrained to consider only those topologies that have the minimum number of links. For terrestrial systems, one of the interesting results is that classical network topologies such as rings and minimum spanning trees are optimal for some conference types. However, no topology is optimal for all types, and some topologies use their capacity very poorly when used for a type for which they were not optimized. Unlike terrestrial networks, satellite networks may be easily configured to have all of their capacity available for all conference types.