Technology for local ATM is currently being offered in a number of devices, such as routers, switches, and switching hubs. These devices provide the capability for an ATM switched internetwork. In general, a switched internetwork consists of an ATM backbone and a number of hubs. The hubs, by providing ATM adaptation functionality, serve as access points to the ATM backbone for servers and clients. The objective of our study is to evaluate alternative strategies for migrating towards an ATM switched internetwork. Our investigation is based on a local area network providing interconnection for a group of clients and servers in a campus environment. A number of different configurations may, at various stages of migration, comprise the interconnection media for this local area network. The network components that are considered in this migration process are Ethernets, both shared and dedicated, multiplexers, hubs, ATM switches, and ATM-equipped end devices. A simulation model is developed to study the performance of the different configurations. Simulation results for end-to-end delay and loss are presented for each alternative configuration.

A network model is developed for studying the effect of multiplexing and switching on broadband network performance. Emphasis is placed on the queuing behavior in the network and the impact of multiplexing and switching on the burstiness of the various traffic streams. The three parameters commonly used to characterize traffic (peak bit rate, mean bit rate, and mean burst length) are also considered, and the dependence of the queuing behavior on these parameters is investigated. The performance of three congestion control schemes based on the leaky bucket algorithm is evaluated. The results provide insight into how call acceptance, bandwidth allocation, and bandwidth enforcement should be implemented in a broadband integrated services digital network (BISDN).>