Application of delta-star topology to multicast network

A significant percentage of traffic will be occupied by various kinds of multicast services, beginning with the broadcasting services in a B-ISDN. In order to reduce the traffic on transmission paths in multicast services, point-to-multipoint connections are used, which are significantly different from the past point-to-point connections. Thus, it is necessary to study the network topology for the case in which multicast services and point-to-point communications services coexist. On the other hand, the delta-star topology has been proposed as a topology effective for enhancing the reliability of the point-to-point communications networks. Since this topology combines the ring topology, which is advantageous for multicasting, and the star topology, which is advantageous for point-to-point communications, this topology is considered to be effective for the case in which both services coexist. In this paper, the network construction cost is evaluated for the cases in which various topologies such as the mesh, star, ring, multiring, and delta-star topologies are applied to communications networks in which multicast services and point-to-point communications services coexist. It has been found that the delta-star topology is optimal for many cases, regardless of the receiving probabilities or transmission bandwidth of various services, transmission path constructed network topologies, and so forth.