As the number of Web users and the diversity of Web applications continues to explode, Web Quality of Service (QoS) is an increasingly critical issue in the domain of e-Commerce [re]. This paper presents experiments designed to estimate users' tolerance of QoS in the context of e-commerce. In addition to objective measures we discuss contextual factors that influence these thresholds and show how users' conceptual models of Web tasks affect their expectations. We then show how user thresholds of tolerance can be taken into account when designing web servers. This integration of user requirements for QoS into systems design is ultimately of benefit to all stakeholders in the design of Internet services.

... makes Quality of Service (QoS) increasingly critical [15]. To date, the majority of research on QoS is systems oriented, focusing on traffic analysis, scheduling, and routing. Relatively minor attention has been paid to user-level QoS issues. It is not yet known how objective system quality relates to users' subjective perceptions of quality. This paper presents the results of quantitative experiments that establish a mapping between objective and perceived QoS in the context of Internet commerce. We also conducted focus groups to determine how contextual factors influence users' perceptions of QoS. We show that, while users' perceptions of World Wide Web QoS are influenced by a number of contextual factors, it is possible to correlate objective measures of QoS with subjective judgements made by users, and therefore influence system design. We argue that only by integrating users' requirements for QoS into system design can the utility of the future Internet be maximized.

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.

Internet traffic is approximately doubling each year. This growth rate applies not only to the entire Internet, but to a large range of individual institutions. For a few places we have records going back several years that exhibit this regular rate of growth. Even when there are no obvious bottlenecks, traffic tends not to grow much faster. This reflects complicated interactions of technology, economics, and sociology, similar to those that have produced “Moore’s Law ” in semiconductors. A doubling of traffic each year represents extremely fast growth, much faster than the increases in other communication services. If it continues, data traffic will surpass voice traffic around the year 2002. However, this rate of growth is slower than the frequently heard claims of a doubling of traffic every three or four months. Such spectacular growth rates apparently did prevail over a two-year period 1995-6. Ever since, though, growth appears to have reverted to the Internet’s historical pattern of a single doubling each year. Progress in transmission technology appears sufficient to double network capacity each year for about the next decade. However, traffic growth faster than a tripling each year could probably not be sustained for more than a few years. Since computing and storage capacities will also be growing, as

The high tech bubble was inflated by myths of astronomical Internet traffic growth rates. Yet although these myths were false, Internet traffic was increasing very rapidly, close to doubling each year since 1997. Moreover, it continues growing close to this rate. This rapid growth reflects a poorly understood combination of many feedback loops operating on different time scales. Evidence about past and current growth rates and their sources is presented, together with speculations about the future. The expected rapid but not astronomical growth of Internet traffic is likely to have important implications for networking technologies that are deployed and for industry structure. Backbone transport is likely to remain a commodity and be provided as a single high quality service. It is probable that backbone revenues will stay low, as the complexity, cost, and revenue and profit opportunities continue to migrate towards the edges of the network.

The popular press often extolls packet networks as much more efficient than switched voice networks in utilizing transmission lines. This impression is reinforced by the delays experienced on the Internet and the famous graphs for traffic patterns through the major exchange points on the Internet, which suggest that networks are running at full capacity. This paper shows the popular impression is incorrect; data networks are very lightly utilized compared to the telephone network. Even the backbones of the Internet are run at lower fractions (10% to 15%) of their capacity than the switched voice network (which operates at over 30% of capacity on average). Private line networks are utilized far less intensively (at 3% to 5%). Further, this situation is likely to persist. The low utilization of data networks compared to voice phone networks is not a symptom of waste. It comes from different patterns of use, lumpy capacity of transmission facilities, and the high growth rate of the indust...

Actual Internet traffic growth rates of 100 percent per year are considerably less than the much-ballyhooed doubling every 3 or 4 months. But even these observed rates are still unprecedented and should be provoking new ways of planning. 1.

Surprisingly little is known about the Internet. Even such basic facts as the size of the networks that make up the Internet or the amount of traffic they carry are not available. This paper presents estimates of the main statistics about the size and growth of the Internet, as well as about utilization patterns. This data is then used to justify some speculative predictions about the likely evolution of data networks.

Differentiated service approach has been proposed as a potential solution to provide Quality of Services (QoS) in the next generation Internet. The ultimate goal of end-to-end service differentiation can be achieved by complementing the network-level QoS with the service differentiation at the Internet servers. In this paper, we have presented a detailed study of the performance of service differentiating web servers (SDIS). Various aspects, such as admission control, scheduling, and task assignment schemes for SDIS have been evaluated through real workload traces. The impact of these aspects have been quantified in the simulation-based study. Under high system utilization, a service differentiating server provides significantly better services to high priority tasks compared to a traditional Internet server. A combination of selective early discard and priority-based task scheduling and assignment is required to provide ecient service differentiation at the servers. The results of these studies could be used as a foundation for further studies on service differentiating Internet servers.

The Internet is the latest in a long succession of communication technologies. The goal of this work is to draw lessons from the evolution of all these services. Little attention is paid to technology as such, since that has changed radically many times. Instead, the stress is on the steady growth in volume of communication, the evolution in the type of traffic sent, the qualitative change this growth produces in how people treat communication, and the evolution of pricing. The focus is on the user, and in particular on how quality and price differentiation have been used by service providers to influence consumer behavior, and how consumers have reacted.