Network Architectures

The Internet is an essential enabler of our daily lives. We aim to understand how it works in practice and we develop new concepts that ensure its robustness for the future.

People

Focus Areas

Aspects that we frequently study include but are not limited to the following:

Internet transport (TCP, QUIC)
The web (HTTP, CDNs)
Video conferencing
Congestion management (congestion control and active queue management)
Network telemetry

Assessing the Internet & Internet Protocols

The Internet is a complex system that is driven by a large number of participants with significant heterogeneity. Hence, while many behaviors are standardized in IETF RFCs, the actual behavior largely depends on how implementers interpret the RFCs with their implementations. As a foundation for our work, we thus strive for creating an understanding of how the Internet and its protocols work in practice. For this, we make use of a large spectrum of methods that range from protocol analysis to testbed-based studies and, ultimately, internet-wide measurements.

Optimizing & Innovating the Internet

In our studies, we frequently find aspects of the Internet that work not as well as they could. Thus, relying on our understanding of the current state of the Internet, we aim to optimize existing methods and develop novel concepts that help in ensuring the robustness of the Internet in the future. Additionally, we study how new paradigms, such as in-network computing, can be conceptually harmonized with the Internet architecture.

Topics that we frequently tackle include but are not limited to the following:

Protocol innovation and optimization
Congestion management
Internet-scale in-network computing (transport issues, COIN, SDN, P4)

IETF / IRTF Contributions

The Internet is system with a very fast development pace. Hence, to keep up with latest Internet innovation and to ensure that our results get traction, we actively participate in the IETF and IRTF. For example, we consider latest trends in congestion management (CCWG, ICCRG), experiment with latest measurement mechanisms (IPPMWG), contribute to making the Internet more sustainable (GREENWG, SUSTAINRG), and have helped shaping future architectures that support in-network computing (COINRG). For this purpose, our members regularly attend IETF meetings.

Teaching Activities

Lectures and Labs

The technologies and concepts that form the basis of our research are prominently featured in our Bachelor-level Datenkommunikation lecture. Some extended concepts are also covered in our Advanced Internet Technology lecture as well as in Communication Systems Engineering.

Our group additionally actively supports our chair’s flagship Bachelor and Master lab ‘Practical Internet eXperience’ to help spread knowledge about the Internet architecture and the operation of CDNs.

Theses

Our group regularly advises a number of theses and we typically have several thesis topics available for motivated and talented students; you can see an excerpt of currently available theses from within the RWTH University network. As we have limited advising capacities, it might be that you do not find any topics published by us. In that case, or if you have specific interests, we encourage you to contact us directly, ideally following the guidelines provided here.

Current Projects

DFG January 2022 - June 2025

LEGATO: LEarninG how to enhAnce neTwork prOtocols

LEGATO aims to address the increasing complexity of network protocols and their performance by developing a methodology for cross-layer optimization that leverages machine learning techniques to capture intricate parameter interdependencies and provide insights into protocol performance.

Cluster of Excellence January 2019 - December 2025

IoP: Internet of Production

The Internet of Production (IoP) aims to enable cross-domain collaboration by sharing semantically adequate and context-related data in real time across global participants. COMSYS contributes to developing IoP infrastructure, integrating engineering models, and supporting digital shadow creation while addressing performance, security, and data sovereignty challenges.

Selected Past Projects

RWTH ERS January 2018 - December 2019

COMTEX: Context in Anonymous Short Texts

COMTEX investigates social and linguistic patterns in anonymous short text exchanges to develop computational methods for addressing anti-social behavior. It combines expertise from linguistics, sociology, and computational fields to understand context in online communities and improve platform design.

Horizon 2020 February 2015 - January 2018

SSICLOPS: Developing the cloud infrastructure for tomorrow

SSICLOPS focuses on developing scalable and secure infrastructures for federated private cloud operations, enabling enterprises to dynamically scale resources while maintaining service levels and security requirements. The project leverages software-defined data centers, inter-cloud communication, and workload optimization tools to maximize performance and resource efficiency across diverse use cases.

DFG January 2013 - December 2024

MAKI: Multi-Mechanisms Adaptation for the Future Internet

MAKI is a Collaborative Research Centre (CRC) focused on enabling automated transitions between functionally equivalent mechanisms in communication systems to address increasing dynamics, variability, and quality requirements. COMSYS contributes to this effort through two sub-projects, focusing on state migration support and architectural concepts for adaptive communication systems.

Selected Publications

Ike Kunze, Constantin Sander, Mike Kosek, Lars Tissen, Jan Pennekamp, Klaus Wehrle. Congestion-Responsive Queuing for Internet Flows. Proceedings of the 2025 IEEE/IFIP Network Operations and Management Symposium (NOMS ‘25), May 12 - May 16, 2025, Honolulu, HI, USA. May 2025.

Ike Kunze, Klaus Wehrle, Dirk Trossen, Marie-José Montpetit, Xavier De Foy, David Griffin, Miguel Rio. Use Cases for In-Network Computing. Internet Research Task Force. December 2024.
expires: 7 June 2025 (work in progress)

Constantin Sander, Ike Kunze, Leo Blöcher, Mike Kosek, Klaus Wehrle. ECN with QUIC: Challenges in the Wild. Proceedings of the Internet Measurement Conference (IMC ‘23), Montreal, Canada. October 2023.

Laurenz Grote, Ike Kunze, Constantin Sander, Klaus Wehrle. Instant Messaging Meets Video Conferencing: Studying the Performance of IM Video Calls. Proceedings of the Network Traffic Measurement and Analysis Conference (TMA ‘23), Jun 26 - Jun 29, 2023, Naples, Italy. June 2023.

Ike Kunze, Dirk Trossen, Klaus Wehrle. Evolving the End-to-End Transport Layer in Times of Emerging Computing In The Network (COIN). Proceedings of the 1st Workshop on New IP and Beyond, co-located with the 30th IEEE International Conference on Network Protocols, Oct 30 - Nov 2, 2022, Lexington, Kentucky, USA. November 2022.

Johannes Krude, Jan Rüth, Daniel Schemmel, Felix Rath, Iohannes-Heorh Folbort, Klaus Wehrle. Determination of Throughput Guarantees for Processor-based SmartNICs. The 17th International Conference on emerging Networking EXperiments and Technologies (CoNEXT ‘21), Virtual Event Germany. December 2021.