— Peer-reviewed work

Publications

ProbeLab team members regularly publish in world-class academic venues. Explore our articles below.

Year Any 2026 2025 2024 2023 2022 2021 2020 2019
2026
IMC '26 Conference Paper ·

Large-Scale Measurement of NAT Traversal for the Decentralized Web: A Case Study of DCUtR in IPFS

Dennis Trautwein · Cornelius Ihle · Moritz Schubotz · Corinna Breitinger · Bela Gipp

The promise of decentralized peer-to-peer (P2P) systems is fundamentally gated by the challenge of Network Address Translation (NAT) traversal, with existing solutions often reintroducing the very centralization they seek to avoid. This paper presents the first large-scale measurement study of a fully decentralized NAT traversal protocol, Direct Connection Upgrade through Relay (DCUtR), within the production libp2p-based InterPlanetary File System (IPFS) network. Drawing on over 4.4 million traversal attempts from 85,000+ distinct networks across 167 countries, we provide an empirical analysis of modern P2P connectivity. We establish a conditional success rate of 70% +- 7.1% for the hole-punching stage, given that prerequisite relay reservation and public address discovery succeed, providing a crucial new benchmark for the field. Critically, we empirically challenge the long-held belief of UDP's superiority for NAT traversal, demonstrating that DCUtR's high-precision, RTT-based synchronization yields statistically indistinguishable success rates for both TCP and QUIC (~70%). Our analysis further validates the protocol's design for permissionless environments by showing that success is independent of relay characteristics and that the mechanism is highly efficient, with 97.6% of successful connections established on the first attempt. Building on this analysis, we propose a concrete roadmap of protocol enhancements aimed at achieving universal connectivity and contribute our complete dataset to foster further research in this domain.

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University Other ·

Measuring and Optimizing Peer-to-Peer Networks: A Case Study of the InterPlanetary File System

Dennis Trautwein

The Internet's transformation from a decentralized network of networks into a landscape dominated by centralized platforms has created systemic risks including infrastructure fragility, censorship vulnerabilities, and concentrated control. While decentralized peer-to-peer systems offer architectural alternatives, they suffer from a fundamental architectural knowledge imbalance: centralized platforms observe all user interactions enabling sophisticated optimization, whereas peer-to-peer networks lack unified observability, hindering both performance analysis and targeted improvements. This dissertation addresses this challenge through comprehensive characterization and optimization of the InterPlanetary File System (IPFS), a prominent peer-to-peer storage network. IPFS's hybrid architecture of combining peer-to-peer networking with strategic centralized components creates fragmented visibility where different subsystems offer complementary but partial vantage points. The research develops measurement methodologies that synthesize these fragmented observations into comprehensive network understanding. It then leverages empirical insights for a targeted protocol optimization. The investigation spans three critical measurement domains. Network topology and content routing performance characterization identified Distributed Hash Table publication latency as the critical bottleneck, with median latencies of 27.7 seconds from Europe. Peer connectivity and Network Address Translation traversal measurements through a novel honeypot methodology established a 70% success rate for decentralized hole-punching across 4.4 million measurements from 167 countries and 85k networks. Usage patterns and content governance analysis revealed a concentration-replication duality where single peers hosted up to 63% of denylist content yet widespread replication ensured only 0.1% of content remained uniquely hosted, complicating coordinated takedown efforts. IPFS' systematic characterization enabled the design and deployment of Optimistic Provide, a backward-compatible protocol optimization achieving order-of-magnitude performance improvements: sub-second publication latency for 90% of operations while reducing network overhead by 40%. The research demonstrates that systematic synthesis of partial observations can overcome the architectural knowledge imbalance, enabling evidence-based optimizations that enhance peer-to-peer systems' viability as alternatives to centralized architectures.

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