arXiv subjects

Leon Janzen

Publications and source records attributed to Leon Janzen.

4 recordsLinked to original sources

arXiv2026

Measuring the End-to-End Resilience of Application Deployments in Real-World Communication Networks with DRACO

Billions of users take Internet connectivity for granted and use it daily to access applications deployed anywhere around the globe. What users perceive as a seamless connection between their end device and the application server involves a complex system of systems operated by various actors. Failures in any of these systems disrupt user-to-application connectivity if the communication network is not resilient. Since communication networks are a critical infrastructure as part of ICT, real-world operators rarely disclose information about them. This makes it difficult to measure the end-to-end resilience of deployments, because it requires guessing topologies and the availability of the involved systems. This paper presents DRACO, a framework for modeling communication networks and measuring end-to-end resilience of application deployments. It enables configuring application deployments across arbitrary communication networks and evaluating their availability, robustness, and resilience. We demonstrate the functional scope of DRACO by modeling nationwide application deployments in Germany and France, highlighting its compatibility with a wide variety of public data sources and synthetic data.

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arXiv2025

Making Cellular Networks Crisis-Proof: Towards Island-Ready, Resilient-By-Design 6G Communication Network

5G and 5G-Advanced cellular networks are vulnerable to regional outages resulting from disasters or targeted attacks. This fragility stems from the reliance on the central core network involved for most 5G connectivity use cases. Crisis-struck regions isolated from the cellular core network form islands, where crisis response is hindered by the unavailability of recovery-relevant services, such as emergency calls, cell broadcasts, messengers, and news apps. Our concept of island-ready, resilient-by-design 6G communication networks envisions local cellular connectivity allowing users to connect to regional application servers, which is currently impossible. In our conceptualization, we follow an all-society approach, as realizing island connectivity requires the cooperation of multiple actors, including users, operators, developers, providers, and authorities. We evaluate how island-ready 5G and 5G-Advanced systems are and outline the open challenges stakeholders must address for full island readiness, such as decentralizing the 6G core network and designing local-first application architectures.

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arXiv2025

The User Perspective on Island-Ready 6G Communication: A Survey of Future Smartphone Usage in Crisis-Struck Areas with Local Cellular Connectivity

Using smartphone apps during crises is well-established, proving critical for efficient crisis response. However, such apps become futile without an Internet connection, which is a common issue during crises. The ongoing 6G standardization explores the capability to provide local cellular connectivity for areas cut off from the Internet in crises. This paper introduces to the HCI community the concept of cellular island connectivity in isolated areas, promising a seamless transition from normal operation to island operation with local-only cellular connectivity. It presents findings from a survey (N = 857) among adult smartphone users from major German cities regarding their smartphone usage preferences in this model. Results show a shift in app demand, with users favoring general-purpose apps over dedicated crisis apps in specific scenarios. We prioritize smartphone services based on their criticality, distinguishing between apps essential for crisis response and those supporting routines. Our findings provide operators, developers, and authorities insights into making user-centric design decisions for implementing island-ready 6G communication.

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arXiv2024

Resilience-by-Design in 6G Networks: Literature Review and Novel Enabling Concepts

The sixth generation (6G) mobile communication networks are expected to intelligently integrate into various aspects of modern digital society, including smart cities, homes, health-care, transportation, and factories. While offering a multitude of services, it is likely that societies become increasingly reliant on 6G infrastructure. Any disruption to these digital services, whether due to human or technical failures, natural disasters, or terrorism, would significantly impact citizens' daily lives. Hence, 6G networks need not only to provide high-performance services but also to be resilient in maintaining essential services in the face of potentially unknown challenges. This paper provides a general review of the state of the art on resilient systems, definitions, concepts, and approaches. Moreover, it introduces a comprehensive concept, i.e., resilience-by-design (RBD), in three different levels for designing resilient 6G communication networks, summarizing our initial studies within the German Open6GHub project. First, we outline the general RBD enabling principles and discuss their related sub-categories. Next, adopting an interdisciplinary approach, we propose to embed these principles across all 6G layers/perspectives including electronics, physical channel, network components and functions, networks, services, and cross-layer and cross-infrastructure considerations and discuss their challenges. We further elaborate the RBD principles and their realizations along with several 6G use-cases. The paper is concluded by presenting a comprehensive list of open problems for future research on 6G resilience.

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