Arrow: A flexible architecture for an accounting and charging infrastructure in the Next Generation Internet

Current pricing and charging methods for the Internet are not based on actual usage of this service, which leads to unfairness and more important, it does not deliver the right signals through financial incentives to network providers to upgrade critical links of their networks. The development of new multimedia applications and the convergence to an integrated services network will foster the tremendous growth of the Internet even more. With the Next Generation Internet not only technical services like bandwidth reservation will be introduced, but also new applications will emerge within the Internet. Charging the Internet in a fashion that provides feedback to users and providers has been proposed since the early '90s, however, only a few implementations and real-world examples are known today. This is due to subsidizing the Internet in its early stages and due to a technical development that did not care much about charging. With the recent redesign of the Internet protocol suite and discussions on multiple service classes in the Internet, architectures for charging and accounting have to be revisited, too. Economic models for the Internet cannot be tested fully and validated in non-real-world environments, because of the unknown user behavior. With this uncertainty over what models and pricing schemes to choose, it is evident that a specific charging and accounting platform will never be accepted by the community. In this paper a novel and flexible architecture for charging and accounting is proposed that provides a wide range of mechanisms and lets researchers experiment in an environment as close as possible to the targeted system. As a first step, four different pricing schemes are described, qualitatively assessed on the proposed platform, and a prototypical implementation performed. One of the economic models that have been implemented on Arrow is based on different service classes including reservation and recalculates prices dynamically depending on the traffic situation. This revised version was published online in August 2006 with corrections to the Cover Date.     

The Aggregation of Climate Change Damages: a Welfare Theoretic Approach

The economic value of environmental goods is commonly determined using the concepts of willingness to pay (WTP) or willingness to accept (WTA). However, the WTP/WTA observed in different countries (or between individuals) will differ according to socio-economic characteristics, in particular income. This notion of differentiated values for otherwise identical goods (say, a given reduction in mortality risk) has been criticized as unethical, most recently in the context of the 'social cost' chapter of the IPCC Second Assessment Report. These critics argue that, being a function of income, WTP/WTA estimates reflect the unfairness in the current income distribution, and for equity reasons uniform per-unit values should therefore be applied across individuals and countries. This paper analyses the role of equity in the aggregation of climate change damage estimates, using basic tools of welfare economics. It shows one way of how WTP/WTA estimates can be corrected in aggregation if the underlying income distribution is considered unfair. It proposes that in the aggregation process individual estimates be weighted with an equity factor derived from the social welfare and utility functions. Equity weighting can significantly increase aggregate (global) damage figures, although some specifications of weighting functions also imply reduced estimates. The paper also shows that while the postulate of uniform per-unit values is compatible with a wide range of 'reasonable' utility and welfare specifications, there are also cases where the common-value notion is not compatible with defensible welfare concepts.