Network Architecture, Protocols, and Services

Networked systems inspired by delay-tolerant, opportunistic, and information-centric architectures to enable and sustain communications in (not just) challenged networking environments.  One important element here is relaxing reliability assumptions and moving towards systems that operate in a best-effort fashion.  To this end, we believe that understanding and, as necessary, revisiting application and protocol design, user interaction patterns, and security mechanisms is crucial. We contribute to the development and evolution of novel architectures and seek to understand their implications on the evolution of the Internet.  In terms of concrete network and system design, we work on opportunistic infrastructure-less information sharing between mobile users; creating Internet (or networked services) accessible to all in an (affordable) manner (digital inclusion); and supporting do-it-yourself networking, including aspects of privacy preservation and censorship resistance.

Adaptive real-time communication for fixed and wireless content distribution and conversational multimedia. We pursue transport protocol and system design and evaluation for scalable and robust multimedia communication, covering error resilience, rate adaptation, and flexible exploitation of network capabilities. The latter may include, for example, multipath operation, overlay mechanisms, and support by intermediaries. Essential elements in research besides modeling and simulations are prototyping applications and experimentation in test beds and the real world.  In particular, we are working with web-based real-time communication (WebRTC) and large-scale IPTV distribution and adaptive streaming.

The above themes rely on growing network measurement efforts to understand the evolving Internet traffic patterns, understand deployment options for future protocols, infer (trends in) user demand and user behavior, assess user-perceived quality of experience, and derive mechanisms for improving performance. We are working on systems for large-scale active end user measurements, particularly on the measurements for web and real-time traffic. We develop models for application behavior and quality of experience assessment which we implement and deploy in a measurement system. We closely cooperate with the NetRadar project.

We are interested in some fundamentals of cloud-based architecture, in the short term including secure and privacy-preserving cloud operation and scalable and adaptive cloud systems. For the longer term, we seek to understand how we can gain flexibility in network- and cloud-based service provisioning by rethinking the basics of networked operating systems. The aim is blurring, and possibly eliminating, the present boundaries between individual computers and network elements to achieve a smoother migration of individual processes or tasks.