The Performance of Measurement-Based Overlay Networks

The literature contains propositions for the use of overlay networks to supplement the normal IP routing functions with higher-level information in order to improve aspects of network behavior. We consider the use of such an overlay to optimize the end-to-end behavior of some special tra c ows. Measurements are used both to construct the virtual links of the overlay and to establish the link costs for use in a link-state routing protocol. The overlay attempts to forward certain packets over the least congested rather than the shortest path. We present simulation results showing that contrary to common belief overlay networks are not always bene cial and can be detrimental

Communicating Climate Change In Internet Discussion Fora: Processes and Implications

Communicating climate change issues in the Internet era requires new strategies that incorporate online communication. The rapid growth of new media and widespread use of the internet has marked everyday lifestyles in modern society. Information on a wide range of social issues, including climate change, is disseminated and debated through online discussions in internet fora. In this research, communication on internet fora and other potential forms of online social interaction are explored, to identify ways to enhance climate change communication on the Internet. The thesis raises three research questions to explore the communication context of internet fora discussion, namely: what are characteristics of the communication process on internet fora? Who is involved in the communication process? What influences do these online communication activities have on users’ everyday activities? The research applies a mixed-methods approach of analysing the usage of Internet fora and the contents of fora communication activities to explore these questions. This includes qualitative reviews of topic-thread discussions to reveal users’ roles in discussions, as well as surveys of fora users. It is argued that with increasing levels of interaction among communicators (people who post or reply to articles in order to express or respond ideas) on internet fora, these communicators are mobilised to join the online discussion process, competing for opinion leadership. The online discussions further contribute to the formation of opinions on climate change, as climate change and related issues are discussed The thesis thereby aims to contribute to the development of effective approaches for opinion formation and climate change communication online, and to encourage individuals to discuss changing behaviour patterns and public engagement of greenhouse gas reduction actions

The Performance of Measurement-Based Overlay Networks

The literature contains propositions for the use of overlay networks to supplement the normal IP routing functions with higher-level information in order to improve aspects of network behavior. We consider the use of such an overlay to optimize the end-to-end behavior of some special tra#c flows. Measurements are used both to construct the virtual links of the overlay and to establish the link costs for use in a link-state routing protocol. The overlay attempts to forward certain packets over the least congested rather than the shortest path. We present simulation results showing that contrary to common belief overlay networks are not always beneficial and can be detrimental