In the management of a modern LAN or campus network, two issues are of key importance, namely network performance and capacity planning. In this paper we report on results from an experimental programme which aims to quantify the performance that can be achieved with a real distributed application running over a range of different network technologies, including Ethernet, ATM, FDDI, and a 100 Mb/s packet-switched LAN. In particular we analyze the contribution of each of the various application and network components to the overall performance experienced by applications. This information will facilitate planning and management of new networks, and permit the identification of `hidden costs' which prevent currently deployed applications from fully exploiting high bandwidth networks.
