Jürgen Quittek

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SPam over Internet Telephony (SPIT) is expected to become a very serious issue in the next years. The threat is going to spin out from the well known email spam problem by bot nets being re-programmed to initiate not just spam emails but also Voice over IP (VoIP) calls. Preventing SPIT is a new problem, because many well-established methods for blocking(More)
114 callee is disturbed by the ringing phone. This paper proposes a novel technique to identify SPIT calls based on typical voice communication patterns. However, as for email spam, a single method will not be sufficient to prevent sufficiently from all SPIT attacks. Therefore, this paper proposes a generic SPIT prevention system architecture that allows to(More)
The Internet architecture is based on design principles such as endto-end addressing and global routeability. It suits relatively static, wellmanaged and flat network hierarchies. Recent years have shown, however, that the Internet is evolving beyond what the current architecture can support. The Internet architecture struggles to support increasingly(More)
Multi-Protocol Label Switching (MPLS) is in the process of standardization by the Internet Engineering Task Force (IETF). It is regarded as a technology for traffic engineering and QoS in IP-networks. In this paper, we address the management of MPLS networks, which is crucial for large networks. We decided to follow the IETF Policy Framework approach and(More)
Thread migration is established as a mechanism for achieving dynamic load sharing. However, fine-grained migration has not been used due to the high thread and messaging overheads. This paper describes a fine-grained thread migration system whose extensible event mechanism permits an efficient interface between threads and communications without(More)
This paper describes the design and implementation of INCA, an open architecture for the distributed management of multi-service networks and systems applications. The Intelligent Network Control Architecture is populated by stationary and mobile intelligent agents. These agents perform monitoring and control of network and systems components, thereby(More)