Can high quality be provided economically for all transmissions on the Internet? Current work assumes that it cannot, and concentrates on providing differentiated service levels. However, an examination of patterns of use and economics of data networks suggests that providing enough bandwidth for uniformly high quality transmission may be practical. If this turns out not to be possible, only the simplest schemes that require minimal involvement by end users and network administrators are likely to be accepted. On the other hand, there are substantial inefficiencies in the current data networks, inefficiencies that can be alleviated even without complicated pricing or network engineering systems.

The simple model on which the Internet has operated, with all packets treated equally, and charges only for access links to the network, has contributed to its explosive growth. However, there is wide dissatisfaction with the delays and losses in current transmission. Further, new services such as packet telephony require assurance of considerably better service. These factors have stimulated the development of methods for providing Quality of Service (QoS), and this will make the Internet more complicated. Differential quality will also force differential pricing, and this will further increase the complexity of the system. The solution of simply putting in more capacity is widely regarded as impractical. However, it appears that we are about to enter a period of rapidly declining transmission costs. The implications of such an environment are explored by considering models with two types of demands for data transport, differing in sensitivity to congestion. Three network configurati...