Network design of b‐isdn using the group virtual path scheme

Abstract

Issues of network design for the group virtual path (GVP) scheme, such as assignment of objective cell loss rates, algorithms for GVPs and congestion tolerance are discussed. The GVP is a previously proposed bandwidth sharing scheme. This scheme gives better statistical multiplexing efficiency since bandwidth is assigned to a group of virtual paths (VPs) rather than to an individual VP.Varying the cell loss rates does not have much effect on the acceptable offered load for low virtual channel (VC) peak speed. The cell loss rate for high VC peak speeds were evaluated by simulation and proved similar to virtual channel handlers (VCHs): switches and virtual path handlers (VPHs): cmss connects. Therefore, objective cell loss rates should be assigned equally to VCHs and VPHs. Five algorithms are proposed for group VPs. The necessary transmission capacity given by each algorithm is slightly higher than optimum grouping but close to optimum groupings can be achieved by using these algorithms together. Congestion tolerance of the GVP scheme is better than that of the conventional VP scheme if only one VP is congested. If all VPs in a GVP are congested, congestion tolerance worsens. However, the transmission capacity necessary to compensate for congestion tolerance is smaller in the GVP scheme than in the conventional scheme.