Network Engineering for ATM with Virtual Paths

Thomas Bauschert Jochen Frings Rainer Siebenhaar Lehrstuhl f ur Kommunikationsnetze Technische Universit at M unchen 80290 M unchen, Germany Summary The asynchronous transfer mode is designed to supply virtual paths (VP). Using these VPs, fully meshed virtual networks can be build on top of the physical backbone network. In this paper we discuss several issues related to the cost optimal dimensioning of VP networks. The dimensioning problem is formulated as a mathematical optimization problem and a solution method is proposed. Results for a 23 node example network will be shown. Introduction Future public ATM networks will have a layered structure consisting of local networks, access networks and a long distance backbone network [1]. Network engineering will be done separately for these subnetworks in order to reduce complexity and to consider speci c demands for each layer. Only backbone facility network engineering problems will be regarded here. Two features of ATM have a substantial impact on these engineering problems: the cell based transmission allowing statistical multiplexing and the possibility to supply virtual paths. In this paper we consider only VPs with deterministic bandwidths that are not subject to statistical cell multiplexing with cells from di erent VPs. Therefore the sum of VP bandwidths on a physical link must not be greater than the link capacity (see gure 1).