Contributions published at Communication Systems Group (Burkhard Stiller)

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Kommunikationssysteme der heutigen Generation ben¨otigen starke Sicherheitsmechanismen um ihren Benutzern einen vertrauenswerten Service anbieten zu k¨onnen. Das Akogrimo Projekt hat sich zum Ziel gesetzt, eine Plattform f ¨ ur mobile Gridsysteme zu entwickeln, die neben den klassischen AAA Konzepten zus¨atzliche Module f ¨ ur Auditing und Charging anbietet (A4C). Der Entwurf von Akogrimo folgt dabei einer serviceorientierten Architektur (SOA), die existierende Implementation eines Prototypen hingegen nicht. In dieser Arbeit wurde ein A4C Gateway erstellt, dass die Konzepte der SOA erf ¨ ullt. Die Evaluation der Leistungsf¨ahigkeit ergab, dass durch die SOA mit erheblich l¨angeren Zugriffszeiten von dreihundert Prozent Steigerung gerechnet werden muss. Today’s communication systems are in need of strong security mechanisms, to be able to provide their users with trustworthy services. The Akogrimo project decided to develop a platform for mobile grid services, which offers not only the classical security modules for authentication, authorisation and accounting but also extends them by adding two additional modules for auditing and charging. The draft version of the developed platform follows an service-oriented architecture (SOA), the existing implementation prototype however does not. The goal for this article is therefore to present an A4C gateway that fulfills the SOA concepts. The evaluation of the performance resulted in the finding, that by adding an additional SOAP-Layer, access times to the A4C functionality raised in value by three-hundred per cent.

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Internet design principles do not focus on commercial service provisioning. Hence, support mechanisms need to be implemented in order to ensure that value added services can be offered in a competitive context. Commercial product offerings base on contractual agreements concluded between service providers and service customers. Contracts need to reflect business-driven requirements originating from involved contract parties, while they are invariably required to respect those regulations imposed by commerce law. Legal compliance, thus, determines the available range of applicable contractual terms—irrespective of whether such a contract governs commercial value added services in the Internet or not. Legal determinations are valid in a limited geographical area. The Internet, however, lacks a distinct notion of location. Consequently, technical means to overcome this fundamental design gap are investigated, in order to ensure that legally compliant contracts can be concluded.

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The provisioning of remote and composed services in support of various application areas has dramatically increased over recent times. Thus, the concept of Grids has evolved, in the sense of a common platform for electronic service provisioning in multi-domain environments. While, traditionally, Grids have seen a quite static existence, many new service compositions have to take place on-demand and for certain periods of time only. To tackle those issues the concept of Virtual Organizations (VO) delivers a highly suitable representation of such dynamic Grids. However, one important open problem at this stage is the lack of applicable, distributed, and efficient accounting schemes for commercial resource and service consumptions. Even for simple management purposes, e.g., sampling or archiving, this functionality is essential. Therefore, a comprehensive model for Grid accounting has been developed and suitable accountable units have been defined, in which an underlying activity- and resource-based accounting model covers economic cost theory. Furthermore, this work is based on a service model proposed for service provisioning in dynamic VOs, overcoming the typically static nature of traditional Grids.

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