Christian Schwartz

• Today's Internet is no longer only controlled by a single stakeholder, e.g. a standard body or a telecommunications company. Rather, the interests of a multitude of stakeholders, e.g. application developers, hardware vendors, cloud operators, and network operators, collide during the development and operation of applications in the Internet. Each of these stakeholders considers different KPIs to be important and attempts to optimise scenarios in its favour. This results in different, often opposing views and can cause problems for theToday's Internet is no longer only controlled by a single stakeholder, e.g. a standard body or a telecommunications company. Rather, the interests of a multitude of stakeholders, e.g. application developers, hardware vendors, cloud operators, and network operators, collide during the development and operation of applications in the Internet. Each of these stakeholders considers different KPIs to be important and attempts to optimise scenarios in its favour. This results in different, often opposing views and can cause problems for the complete network ecosystem. One example of such a scenario are Signalling Storms in the mobile Internet, with one of the largest occurring in Japan in 2012 due to the release and high popularity of a free instant messaging application. The network traffic generated by the application caused a high number of connections to the Internet being established and terminated. This resulted in a similarly high number of signalling messages in the mobile network, causing overload and a loss of service for 2.5 million users over 4 hours. While the network operator suffers the largest impact of this signalling overload, it does not control the application. Thus, the network operator can not change the application traffic characteristics to generate less network signalling traffic. The stakeholders who could prevent, or at least reduce, such behaviour, i.e. application developers or hardware vendors, have no direct benefit from modifying their products in such a way. This results in a clash of interests which negatively impacts the network performance for all participants. The goal of this monograph is to provide an overview over the complex structures of stakeholder relationships in today's Internet applications in mobile networks. To this end, we study different scenarios where such interests clash and suggest methods where tradeoffs can be optimised for all participants. If such an optimisation is not possible or attempts at it might lead to adverse effects, we discuss the reasons.…
• Modellierung und Bewertung von Szenarien mit mehreren Akteuren in Kommunikationsnetzen