Structured systems analysis methodology for design of an ATM network architecture

The asynchronous transfer mode (ATM) network design problem is treated as a resource-allocation problem. Traffic control is applied to different entities: packets, bursts, calls, and flows. Each of these entities can be controlled locally, within an exchange, or globally, at the network level. This gives rise to a multistrata architecture, where the resource-allocation stratum is defined both by the layer of traffic flow and the control level. Dedicated and virtual connections can be set up in all strata: for bursts, calls, subscriptions, and flows, at the exchange, subnetwork, and network levels. The open systems interconnection protocols are used to map heterogeneous user entities onto uniform network entities. The critical load is defined, which is where burst and call fluctuations begin to result in long queues and big packet delays. The critical load is used to determine thresholds, at the network and exchange level, for the number of virtual or dedicated connections which can be established in each traffic class