Leonard Bradatsch

Service Function Chaining (SFC) enables dynamic steering of traffic through a set of service functions based on classification of packets, allowing network operators fine-grained and flexible control of packet flows. New paradigms like Zero Trust (ZT) pose additional requirements to the security of network architectures. This includes client authentication, confidentiality, and integrity throughout the whole network, while also being able to perform operations on the unencrypted payload of packets. However, these requirements are only partially addressed in existing SFC literature. Therefore, we first present a comprehensive analysis of the security requirements for SFC architectures. Based on this analysis, we propose a concept towards the fulfillment of the requirements while maintaining the flexibility of SFC. In addition, we provide and evaluate a proof of concept implementation, and discuss the implications of the design choices.

There are many high-speed TCP variants with different congestion control algorithms, which are designed for specific settings or use cases. Distinct features of these algorithms are meant to optimize different aspects of network performance, and the choice of TCP variant strongly influences application performance. However, setting up tests to help with the decision of which variant to use can be problematic, as many systems are not designed to deal with high bandwidths, such as 10 Gbps or more. This paper provides an overview of pitfalls and challenges of realistic network analysis to help in the decision making process.

The increasing availability of 10G Ethernet network capabilities challenges existing transport layer protocols. As 10G connections gain momentum outside of backbone networks, the choice of appropriate TCP congestion control algorithms becomes even more relevant for networked applications running in environments such as data centers. Therefore, we provide an extensive overview of relevant TCP congestion control algorithms for high-speed environments leveraging 10G. We analyzed and evaluated six TCP variants using a physical network testbed, with a focus on the effects of propagation delay and significant drop rates. The results indicate that of the algorithms compared, BIC is most suitable when no legacy variant is present, CUBIC is suggested otherwise.

Research in human-computer interaction often requires the acquisition of self-reported data. Particularly concerning serious games, the interaction between the game and the user still holds many unknown aspects, partly due to the user's double role as player and learner. An easy way of collecting data consists of questionnaires, mostly employed in pen-and-paper or electronic form. In order to gather data points during game play, the player is interrupted, potentially causing unintentional side effects. We suggest an integration of questionnaires into games as game elements, in order to mitigate the effects of interruption. A serious game prototype with an integrated survey was implemented, and evaluated regarding its effects on the players' experience of presence.