Publications

    2022

  1. IXP Scrubber: Learning from Blackholing Traffic for ML-Driven DDoS Detection at Scale
    Matthias Wichtlhuber, Eric Strehle, Lars Prepens, Alina Rubina, Daniel Kopp, Stefan Stegmüller, Christoph Dietzel, Oliver Hohlfeld
    Conference: ACM SIGCOMM 2022
    PDF
  2. SIGCOMM'22
  3. Data-Driven Study of Long-Term Gaming Experience
    Jens Helge Reelfs, Oliver Hohlfeld
    Conference: IEEE Conference on Quality of Multimedia Experience 2022
    PDF data
  4. QoMEX'22
  5. Recommendations for Designing Hybrid Conferences
    Vaibhav Bajpai, Oliver Hohlfeld, Jon Crowcroft, Srinivasan Keshav, Henning Schulzrinne, Jörg Ott, Simone Ferlin, Georg Carle, Andrew Hines, Alexander Raake
    Journal: ACM SIGCOMM Computer Communication Review, Volume 52, Issue 2, April 2022
    PDF
  6. CCR'22
  7. Interpreting Emoji with Emoji: 🏖️ => ☀️😎🌊
    Jens Helge Reelfs, Timon Mohaupt, Sandipan Sikdar, Markus Strohmaier, Oliver Hohlfeld
    Conference: 5th International Workshop on Emoji Understanding and Applications in Social Media 2022
    PDF video
  8. Emoji'22
  9. Characterizing the country-wide adoption and evolution of the Jodel messaging app in Saudi Arabia
    Helge Reelfs, Oliver Hohlfeld, Markus Strohmaier, Niklas Henckell
    Journal: Webscience Journal 2022
    PDF arXiv
  10. Webscience Journal'22
  11. Anonymous Hyperlocal Communities: What do they talk about?
    Jens Helge Reelfs, Oliver Hohlfeld, Niklas Henckell
    Conference: WWW LocWeb Workshop 2022
    PDF arXiv
  12. WWW LocWeb'22
  13. Lights on Power Plant Control Networks
    Stefan Mehner, Franka Schuster, Oliver Hohlfeld
    Conference: Passive and Active Measurement Conference 2022
    PDF
    Abstract: Industrial Control Systems (ICS) are critical systems to our society. Yet they are less studied given their closed nature and often the unavailability of data. While few studies focus on wide-area SCADA systems, e.g., power or gas distribution networks, mission critical networks that control power generation are not yet studied. To address this gap, we perform the first measurement study of Distributed Control System (DCS) by analyzing traces from all network levels from several operational power plants. We show that DCS networks feature a rather rich application mix compared to wide-area SCADA networks and that applications and sites can be fingerprinted with statistical means. While traces from operational power plants are hard to obtain, we analyze to which extent easier to access training facilities can be used as vantage points. Our study aims to shed light on traffic properties of critical industries that were not yet analyzed given the lack of data.
  14. PAM'22
  15. Differences in Social Media Interactions Exist Between Western and Middle-East Countries
    Jens Helge Reelfs, Oliver Hohlfeld, Niklas Henckell
    Conference: Passive and Active Measurement Conference 2022
    PDF arXiv video
    Abstract: In this paper, we empirically analyze two examples of a Western (DE) versus Middle-East (SA) Online Social Messaging App. By focusing on the system interactions over time in comparison, we identify inherent differences in user engagement. We take a deep dive and shed light onto differences in user attention shifts and showcase their structural implications to the user experience. Our main findings show that in comparison to the German counterparts, the Saudi communities prefer creating content in longer conversations, while voting more conservative.
  16. PAM'22
  17. An Empirical View on Consolidation of the Web
    Trinh Viet Doan, Roland van Rijswijk-Deij, Oliver Hohlfeld, Vaibhav Bajpai
    Journal: ACM Transactions on Internet Technology (TOIT), Volume 22, Aug 2022
    PDF video
    Abstract: The majority of Web content is delivered by only a few companies that provide Content Delivery Infrastructuress (CDIss) such as Content Delivery Networkss (CDNss) and cloud hosts. Due to increasing concerns about trends of centralization, empirical studies on the extent and implications of resulting Internet consolidation are necessary. Thus, we present an empirical view on consolidation of the Web by leveraging datasets from two different measurement platforms. We first analyze Web consolidation around CDIs at the level of landing webpages, before narrowing down the analysis to a level of embedded page resources. The datasets cover 1(a) longitudinal measurements of DNS records for 166.5 M Web domains over five years, 1(b) measurements of DNS records for Alexa Top 1 M over a month and (2) measurements of page loads and renders for 4.3 M webpages, which include data on 392.3 M requested resources. We then define CDIs penetration as the ratio of CDI-hosted objects to all measured objects, which we use to quantify consolidation around CDIs. We observe that CDI penetration has close to doubled since 2015, reaching a lower bound of 15% for all .com, .net, and .org Web domains as of January 2020. Overall, we find a set of six CDIss to deliver the majority of content across all datasets, with these six CDIss being responsible for more than 80% of all 221.9 M CDI-delivered resources (56.6% of all resources in total). We find high dependencies of Web content on a small group of CDIss, in particular, for fonts, ads, and trackers, as well as JavaScript resources such as jQuery. We further observe CDIss to play important roles in rolling out IPv6 and TLS 1.3 support. Overall, these observations indicate a potential oligopoly, which brings both benefits but also risks to the future of the Web.
  18. TOIT'22

    2021

  19. United We Stand: Collaborative Detection and Mitigation of Amplification DDoS Attacks at Scale
    Daniel Wagner, Daniel Kopp, Matthias Wichtlhuber, Christoph Dietzel, Oliver Hohlfeld, Georgios Smaragdakis, Anja Feldmann
    Conference: ACM Conference on Computer and Communications Security 2021
    PDF DOI video 2022 IETF/IRTF Applied Networking Research Prize
  20. CCS'21
  21. CyberBunker 2.0 - A Domain and Traffic Perspective on a Bullet Proof Hoster
    Daniel Kopp, Eric Strehle, Oliver Hohlfeld
    Conference: ACM Conference on Computer and Communications Security (Poster) 2021
    PDF arXiv video
  22. CCS-Poster'21
  23. Large Scale Outage Visibility on the Control Plane
    Leonard Becker, Oliver Hohlfeld, Georgios Smaragdakis
    Conference: ACM CoNEXT Student 2021
    PDF DOI
  24. CoNEXT Student'21
  25. A Questionnaire to Assess Virtual Conference Participation Experience
    Oliver Hohlfeld, Dennis Guse, Katrien De Moor
    Conference: IEEE Conference on Quality of Multimedia Experience 2021
    PDF video
  26. QoMEX'21
  27. Blocklist Babel: On the Transparency and Dynamics of Open Source Blocklisting
    Álvaro Feal, Pelayo Vallina, Julien Gamba, Sergio Pastrana, Antonio Nappa, Oliver Hohlfeld, Narseo Vallina-Rodriguez, Juan Tapiador
    Journal: IEEE Transactions on Network and Service Management, Volume 2021
    PDF DOI
  28. TNSM'21
  29. A Year in Lockdown: How the Waves of COVID-19 Impact Internet Traffic
    Anja Feldmann, Oliver Gasser, Franziska Lichtblau, Enric Pujol, Ingmar Poese, Christoph Dietzel, Daniel Wagner, Matthias Wichtlhuber, Juan Tapiador, Narseo Vallina-Rodriguez, Oliver Hohlfeld, Georgios Smaragdakis
    Journal: Communications of the ACM, Volume 7, Issue 64 2021
    PDF Research Highlight
    [ Technical Perspective on our Article written by Jennifer Rexford (Princeton University) ]
  30. CACM'21
  31. Implications of the COVID-19 Pandemic on the Internet Traffic
    Anja Feldmann, Oliver Gasser, Franziska Lichtblau, Enric Pujol, Ingmar Poese, Christoph Dietzel, Daniel Wagner, Matthias Wichtlhuber, Juan Tapiador, Narseo Vallina-Rodriguez, Oliver Hohlfeld, Georgios Smaragdakis
    Conference: ITG-Symposium on Broadband Coverage in Germany 2021
    PDF
    [ Invited paper ]
  32. ITG'21
  33. Understanding & Predicting User Lifetime with Machine Learning in an Anonymous Location-Based Social Network
    Jens Helge Reelfs, Max Bergmann, Oliver Hohlfeld, Niklas Henckell
    Conference: WWW LocWeb Workshop 2021
    PDF arXiv DOI slides
  34. WWW LocWeb'21
  35. DDoS Never Dies? An IXP Perspective on DDoS Amplification Attacks
    Daniel Kopp, Christoph Dietzel, Oliver Hohlfeld
    Conference: Passive and Active Measurement Conference 2021
    arXiv video
    [ Daniel’s talk at the RIPE 82 Anti Abuse WG meeting ]
  36. PAM'21

    2020

  37. The Boon and Bane of Cross-Signing: Shedding Light on a Common Practice in Public Key Infrastructures
    Jens Hiller, Johanna Amann, Oliver Hohlfeld
    Conference: ACM Conference on Computer and Communications Security 2020
    arXiv DOI
    Abstract: Public Key Infrastructures (PKIs) with their trusted Certificate Authorities (CAs) provide the trust backbone for the Internet: CAs sign certificates which prove the identity of servers, applications, or users. To be trusted by operating systems and browsers, a CA has to undergo lengthy and costly validation processes. Alternatively, trusted CAs can cross-sign other CAs to extend their trust to them. In this paper, we systematically analyze the present and past state of cross-signing in the Web PKI. Our dataset (derived from passive TLS monitors and public CT logs) encompasses more than 7 years and 225 million certificates with 9.3 billion trust paths. We show benefits and risks of cross-signing. We discuss the difficulty of revoking trusted CA certificates where, worrisome, cross-signing can result in valid trust paths to remain after revocation; a problem for non-browser software that often blindly trusts all CA certificates and ignores revocations. However, cross-signing also enables fast bootstrapping of new CAs, e.g., Let’s Encrypt, and achieves a non-disruptive user experience by providing backward compatibility. In this paper, we propose new rules and guidance for cross-signing to preserve its positive potential while mitigating its risks.
  38. CCS'20
  39. The Lockdown Effect: Implications of the COVID-19 Pandemic on Internet Traffic
    Anja Feldmann, Oliver Gasser, Franziska Lichtblau, Enric Pujol, Ingmar Poese, Christoph Dietzel, Daniel Wagner, Matthias Wichtlhuber, Juan Tapiador, Narseo Vallina-Rodriguez, Oliver Hohlfeld, Georgios Smaragdakis
    Conference: ACM Internet Measurement Conference 2020
    PDF arXiv DOI video
    Abstract: Due to the COVID-19 pandemic, many governments imposed lock-downs that forced hundreds of millions of citizens to stay at home. The implementation of confinement measures increased Internet traffic demands of residential users, in particular, for remote working, entertainment, commerce, and education, which, as a result, caused traffic shifts in the Internet core.In this paper, using data from a diverse set of vantage points (one ISP, three IXPs, and one metropolitan educational network), we examine the effect of these lockdowns on traffic shifts. We find that the traffic volume increased by 15-20% almost within a week—while overall still modest, this constitutes a large increase within this short time period. However, despite this surge, we observe that the Internet infrastructure is able to handle the new volume, as most traffic shifts occur outside of traditional peak hours. When looking directly at the traffic sources, it turns out that, while hypergiants still contribute a significant fraction of traffic, we see (1) a higher increase in traffic of non-hypergiants, and (2) traffic increases in applications that people use when at home, such as Web conferencing, VPN, and gaming. While many networks see increased traffic demands, in particular, those providing services to residential users, academic networks experience major overall decreases. Yet, in these networks, we can observe substantial increases when considering applications associated to remote working and lecturing.
  40. IMC'20
  41. Mis-shapes, Mistakes, Misfits: An Analysis of Domain Classification Services
    Pelayo Vallina, Victor Le Pochat, Alvaro Feal, Marius Paraschiv, Julien Gamba, Tim Burke, Oliver Hohlfeld, Juan Tapiador, Narseo Vallina-Rodriguez
    Conference: ACM Internet Measurement Conference 2020
    PDF DOI video
    Abstract: Domain classification services have applications in multiple areas, including cybersecurity, content blocking, and targeted advertising. Yet, these services are often a black box in terms of their methodology to classifying domains, which makes it difficult to assess their strengths, aptness for specific applications, and limitations. In this work, we perform a large-scale analysis of 13 popular domain classification services on more than 4.4M hostnames. Our study empirically explores their methodologies, scalability limitations, label constellations, and their suitability to academic research as well as other practical applications such as content filtering. We find that the coverage varies enormously across providers, ranging from over 90% to below 1%. All services deviate from their documented taxonomy, hampering sound usage for research. Further, labels are highly inconsistent across providers, who show little agreement over domains, making it difficult to compare or combine these services. We also show how the dynamics of crowd-sourced efforts may be obstructed by scalability and coverage aspects as well as subjective disagreements among human labelers. Finally, through case studies, we showcase that most services are not fit for detecting specialized content for research or content-blocking purposes. We conclude with actionable recommendations on their usage based on our empirical insights and experience. Particularly, we focus on how users should handle the significant disparities observed across services both in technical solutions and in research.
  42. IMC'20
  43. Corona-Warn-App: Tracing the Start of the Official COVID-19 Exposure Notification App for Germany
    Jens Helge Reelfs, Oliver Hohlfeld, Ingmar Poese
    Conference: ACM SIGCOMM Poster 2020
    PDF arXiv DOI slides
  44. SIGCOMM Poster'20
  45. Tracking the deployment of TLS 1.3 on the Web: A story of experimentation and centralization
    Ralph Holz, Jens Hiller, Johanna Amann, Abbas Razaghpanah, Thomas Jost, Narseo Vallina-Rodriguez, Oliver Hohlfeld
    Journal: ACM SIGCOMM Computer Communication Review, Volume 50, Issue 3, Jul 2020
    PDF code data
  46. CCR'20
  47. Lessons Learned Organizing the PAM 2020 Virtual Conference
    Chris Misa, Dennis Guse, Oliver Hohlfeld, Ramakrishnan Durairajan, Anna Sperotto, Alberto Dainotti, Reza Rejaie
    Journal: ACM SIGCOMM Computer Communication Review, Volume 50, Issue 3, Jul 2020
    PDF data
  48. CCR'20
  49. Multi-episodic Perceived Quality of an Audio-on-Demand Service
    Dennis Guse, Oliver Hohlfeld, Anna Wunderlich, Benjamin Weiss, Sebastian Moeller
    Conference: IEEE Conference on Quality of Multimedia Experience 2020
    PDF arXiv
  50. QoMEX'20
  51. Word-Emoji embeddings from large scale messaging data reflect real world semantic associations of expressive icons
    Helge Reelfs, Oliver Hohlfeld, Markus Strohmaier, Niklas Henckell
    Conference: ICWSM Workshop on Emoji Understanding and Applications in Social Media 2020
    PDF arXiv
  52. ICWSM Emoji'20
  53. General Knapsack Bounds of Web Caching Performance Regarding the Properties of each Cacheable Object
    Gerhard Hasslinger, Konstantinos Ntougias, Frank Hasslinger, Oliver Hohlfeld
    Conference: Global Internet Symposium 2020
    PDF
  54. GI'20
  55. MUST, SHOULD, DON'T CARE: TCP conformance in the wild
    Mike Kosek, Leo Blöcher, Jan Rüth, Torsten Zimmermann, Oliver Hohlfeld
    Conference: Passive and Active Measurement Conference 2020
    arXiv video code
    [ Mike’s talk @ IRTF MAPRG Aug'20 ]
  56. PAM'20
  57. Congestion Control in the Wild - Investigating Content Provider Fairness
    Ike Kunze, Jan Rüth, Oliver Hohlfeld
    Journal: IEEE Transactions on Network and Service Management, Volume 17, Issue 2, Jun, pages 1224--1238 2020
    PDF DOI
  58. TNSM'20

    2019

  59. DDoS Hide & Seek: On the Effectiveness of a Booter Services Takedown
    Daniel Kopp, Matthias Wichtlhuber, Ingmar Poese, José Jair Cardoso de Santanna, Oliver Hohlfeld, Christoph Dietzel
    Conference: ACM Internet Measurement Conference 2019
    PDF DOI slides video
    [ Daniel’s Talk at LACNIC meeting ]
  60. IMC'19
  61. Hidden Treasures -- Recycling Large-Scale Internet Measurements to Study the Internet's Control Plane
    Jan R̈uth, Torsten Zimmermann, Oliver Hohlfeld
    Conference: Passive and Active Measurement Conference 2019
    arXiv DOI slides
  62. PAM'19
  63. An Empirical View on Content Provider Fairness
    Jan Rüth, Ike Kunze, Oliver Hohlfeld
    Conference: TMA 2019
    PDF arXiv DOI
  64. TMA'19
  65. Perceiving QUIC: Do Users Notice or Even Care?
    Jan Rüth, Konrad Wolsing, Klaus Wehrle, Oliver Hohlfeld
    Conference: ACM CoNEXT 2019
    PDF arXiv DOI data
  66. CoNEXT'19
  67. A Performance Perspective on Web Optimized Protocol Stacks: TCP+TLS+HTTP/2 vs. QUIC
    Konrad Wolsing, Jan Rüth, Klaus Wehrle, Oliver Hohlfeld
    Conference: ACM Applied Networking Research Workshop 2019
    PDF arXiv DOI
  68. ANRW'19
  69. Determining Response-generating Contexts on Microblogging Platforms
    Jennifer Fest, Arndt Heilmann, Oliver Hohlfeld, Stella Neumann, Jens Helge Reelfs, Marco Schmitt, Alina Vogelgesang
    Conference: Conference on Natural Language Processing (KONVENS) 2019
    PDF
    [ Venue in linguistics ]
  70. KONVENS'19
  71. DeePCCI: Deep Learning-based Passive Congestion Control Identification
    Constantin Sander, Jan Rüth, Oliver Hohlfeld, Klaus Wehrle
    Conference: ACM SIGCOMM Workshop on Network Meets AI & ML 2019
    PDF arXiv DOI
  72. SIGCOMM NetAI'19
  73. TheFragebogen: A Web Browser-based Questionnaire Framework for Scientific Research
    Dennis Guse, Henrique R. Orefice, Gabriel Reimers, Oliver Hohlfeld
    Conference: IEEE Conference on Quality of Multimedia Experience 2019
    PDF arXiv DOI code
    [ Project page: thefragebogen.de ]
  74. QoMEX'19
  75. The Case for Session Sharing: Relieving Clients from TLS Handshake Overheads
    Jens Hiller, Martin Henze, Torsten Zimmermann, Oliver Hohlfeld, Klaus Wehrle
    Conference: IEEE LCN Symposium on Emerging Topics in Networking 2019
    PDF DOI
  76. LCN'19
  77. Fast and Efficient Web Caching Methods Regarding the Size and Performance Measures per Data Object
    Gerhard Hasslinger, Konstantinos Ntougias, Frank Hasslinger, Oliver Hohlfeld
    Conference: IEEE International Workshop on Computer Aided Modeling and Design of Communication Links and Networks (CAMAD) 2019
    DOI
  78. CAMAD'19
  79. Demystifying the Performance of Offloaded Packet Processing
    Oliver Hohlfeld, Johannes Krude, Jens Helge Reelfs, Jan R̈uth, Klaus Wehrle
    Conference: IEEE Netsoft 2019
    DOI
    Abstract: High packet rates at ≥ 10 GBit/s challenge the packet processing performance of network stacks. A common solution is to offload (parts of) the user-space packet processing to other execution environments, e.g., into the device driver (kernel-space), the NIC or even from virtual machines into the host operating system (OS), or any combination of those. While common wisdom states that offloading optimizes performance, neither benefits nor negative effects are comprehensively studied. In this paper, we aim to shed light on the benefits and shortcomings of eBPF/XDP-based offloading from the user-space to i) the kernel-space or ii) a smart NIC-including VM virtualization. We show that offloading can indeed optimize packet processing, but only if the task is small and optimized for the target environment. Otherwise, offloading can even lead to detrimental performance.
  80. Netsoft'19
  81. Hashtag Usage in a Geographically-Local Microblogging App
    Helge Reelfs, Timon Mohaupt, Oliver Hohlfeld, Niklas Henckell
    Conference: WWW LocWeb Workshop 2019
    arXiv DOI
    Abstract: This paper studies for the first time the usage and propagation of hashtags in a new and fundamentally different type of social media that is i) without profiles and ii) location-based to only show nearby posted content. Our study is based on analyzing the mobile-only Jodel microblogging app, which has an established user base in several European countries and Saudi Arabia. All posts are user to user anonymous (i.e., no displayed user handles) and are only displayed in the proximity of the user’s location (up to 20 km). It thereby forms local communities and opens the question of how information propagates within and between these communities. We tackle this question by applying established metrics for Twitter hashtags to a ground-truth data set of Jodel posts within Germany that spans three years. We find the usage of hashtags in Jodel to differ from Twitter; despite embracing local communication in its design, Jodel hashtags are mostly used country-wide.
  82. WWW LocWeb'19
  83. Hi Doppelgänger: Towards Detecting Manipulation in News Comments
    Jan Pennekamp, Martin Henze, Oliver Hohlfeld, Andriy Panchenko
    Conference: WWW Cybersafety Workshop 2019
    DOI
    Abstract:

    Public opinion manipulation is a serious threat to society, potentially influencing elections and the political situation even in established democracies. The prevalence of online media and the opportunity for users to express opinions in comments magnifies the problem. Governments, organizations, and companies can exploit this situation for biasing opinions. Typically, they deploy a large number of pseudonyms to create an impression of a crowd that supports specific opinions. Side channel information (such as IP addresses or identities of browsers) often allows a reliable detection of pseudonyms managed by a single person. However, while spoofing and anonymizing data that links these accounts is simple, a linking without is very challenging.

    In this paper, we evaluate whether stylometric features allow a detection of such doppelgängers within comment sections on news articles. To this end, we adapt a state-of-the-art doppelgänger detector to work on small texts (such as comments) and apply it on three popular news sites in two languages. Our results reveal that detecting potential doppelgängers based on linguistics is a promising approach even when no reliable side channel information is available. Preliminary results following an application in the wild shows indications for doppelgängers in real world data sets.

  84. WWW Cybersafety'19
  85. TCP's Initial Window –- Deployment in the Wild and its Impact on Performance
    Jan Rüth, Ike Kunze, Oliver Hohlfeld
    Journal: IEEE Transactions on Network and Service Management, Volume 16, Issue 2, Jun 2019
    PDF DOI
  86. TNSM'19
  87. Blitz-starting QUIC Connections
    Jan Rüth, Konrad Wolsing, Martin Serror, Klaus Wehrle, Oliver Hohlfeld
    TechReport: arXiv:1905.03144 2019
    PDF
  88. arXiv'19
  89. Application-Agnostic Offloading of Packet Processing
    Oliver Hohlfeld, Helge Reelfs, Jan Rüth, Florian Schmidt, Torsten Zimmermann, Jens Hiller, Klaus Wehrle
    TechReport: arXiv:1904.00671 2019
    PDF
  90. arXiv'19

    2018

  91. Is the Web ready for HTTP/2 Server Push?
    Torsten Zimmermann, Benedikt Wolters, Oliver Hohlfeld, Klaus Wehrle
    Conference: ACM CoNEXT 2018
    arXiv DOI code
  92. CoNEXT'18
  93. A Long Way to the Top: Significance, Structure, and Stability of Internet Top Lists
    Quirin Scheitle, Oliver Hohlfeld, Julien Gamba, Jonas Jelten, Torsten Zimmermann, Stephen D. Strowes, Narseo Vallina-Rodriguez
    Conference: ACM Internet Measurement Conference 2018
    arXiv DOI data ACM IMC Community Contribution Award
    [ Press: netzpolitik.org ]
  94. IMC'18
  95. Digging into Browser-based Crypto Mining
    Jan Rüth, Torsten Zimmermann, Konrad Wolsing, Oliver Hohlfeld
    Conference: ACM Internet Measurement Conference 2018
    arXiv DOI
    [ MIT Technology Review: This week’s most thought-provoking papers
    Press: theregister.co.uk bitcoinist dailyhoodle.com ftreporter.com banklesstimes.com eyerys.com coincrispy.com playtech.ro webtekno.com digitaltrends.com bitcoin.com oracletimes.com thenextweb.com ]
  96. IMC'18
  97. Dissecting Apple's Meta-CDN during an iOS Update
    Jeremias Blendin, Fabrice Bendfeldt, Ingmar Poese, Boris Koldehofe, Oliver Hohlfeld
    Conference: ACM Internet Measurement Conference 2018
    arXiv DOI
  98. IMC'18
  99. Operating a DNS-based Active Internet Observatory
    Oliver Hohlfeld
    Conference: ACM SIGCOMM Poster 2018
    PDF
  100. SIGCOMM Poster'18
  101. Demystifying TCP Initial Window Configurations of Content Distribution Networks
    Jan Rüth, Oliver Hohlfeld
    Conference: Network Traffic Measurement and Analysis Conference 2018
    PDF
  102. TMA'18
  103. A First Look at Certification Authority Authorization (CAA)
    Quirin Scheitle, Taejoong Chung, Jens Hiller, Oliver Gasser, Johannes Naab, Roland van Rijswijk-Deij, Oliver Hohlfeld, Ralph Holz, Dave Choffnes, Alan Mislove, Georg Carle
    Journal: C_CCR, Apr 2018
    PDF DOI data
  104. CCR'18
  105. A First Look at QUIC in the Wild
    Jan Rüth, Ingmar Poese, Christoph Dietzel, Oliver Hohlfeld
    Conference: Passive and Active Measurement Conference 2018
    arXiv DOI slides video data
    [ Video of Jan’s talk at IETF-101 ]
  106. PAM'18
  107. Characterizing a Meta-CDN
    Oliver Hohlfeld, Jan Rüth, Konrad Wolsing, Torsten Zimmermann
    Conference: Passive and Active Measurement Conference 2018
    arXiv DOI slides
  108. PAM'18
  109. Structure and Stability of Internet Top Lists
    Quirin Scheitle, Jonas Jelten, Oliver Hohlfeld, Luca Ciprian, Georg Carle
    TechReport: PAM Poster arXiv:1802.02651 2018
  110. PAM Poster'18
  111. Application-Agnostic Offloading of Datagram Processing
    Oliver Hohlfeld, Jens Helge Reelfs, Jan R̈uth, Florian Schmidt, Torsten Zimmermann, Jens Hiller, Klaus Wehrle
    Conference: International Teletraffic Congress 2018
    PDF
  112. ITC'18
  113. Comparing Web Cache Implementations for Fast O(1) Updates Based on LRU, LFU and Score Gated Strategies
    Gerhard Hasslinger, Konstantinos Ntougias, Frank Hasslinger, Oliver Hohlfeld
    Conference: IEEE International Workshop on Computer Aided Modeling and Design of Communication Links and Networks (CAMAD) 2018
  114. CAMAD'18
  115. Optimum Caching versus LRU/LFU Methods: Comparison and Combined Limited Look-Ahead Strategies
    Gerhard Hasslinger, Juho Heikkinen, Konstantinos Ntougias, Frank Hasslinger, Oliver Hohlfeld
    Conference: 3rd Content Caching and Delivery in Wireless Networks Workshop 2018
    DOI
  116. '18
  117. Scalability Issues and Solutions for Software Defined Networks (Editorial)
    Oliver Hohlfeld, James Kempf, Martin Reisslein, Stefan Schmid, Nadir Shah
    Journal: IEEE JSAC Special Issue on Scalability Issues and Solutions for Software Defined Networks, Volume 36, Issue 12, dec 2018
    DOI
  118. JSAC'18
  119. Security and Performance of Software-defined Networks and Functions Virtualization
    David Hausheer, Oliver Hohlfeld, Stefan Schmid, Guofei Gu
    Journal: Elsevier Computer Networks, Volume 138, Issue 19, Jun, pages 15--17 2018
    DOI
  120. Comnet'18
  121. Giving Customers Control over Their Data: Integrating a Policy Language into the Cloud
    Jens Hiller, Maël Kimmerlin, Max Plauth, Seppo Heikkil̈a, Stefan Klauck, Ville Lindfors, Felix Eberhardt, Dariusz Bursztynowski, Jesus Llorente Santos, Oliver Hohlfeld, Klaus Wehrle
    Conference: IEEE International Conference on Cloud Engineering (IC2E) 2018
    PDF DOI
  122. IC2E'18
  123. A Quantitative Analysis of the Impact of Arbitrary Blockchain Content on Bitcoin
    Roman Matzutt, Jens Hiller, Martin Henze, Jan H. Ziegeldorf, Dirk M̈ullmann, Oliver Hohlfeld, Klaus Wehrle
    Conference: International Conference on Financial Cryptography and Data Security (FinancialCrypto) 2018
    PDF
  124. FinancalCrypto'18

    2017

  125. Large-Scale Scanning of TCP's Initial Window
    Jan Rüth, Christian Bormann, Oliver Hohlfeld
    Conference: ACM Internet Measurement Conference 2017
    PDF
  126. IMC'17
  127. A QoE Perspective on HTTP/2 Server Push
    Torsten Zimmermann, Benedikt Wolters, Oliver Hohlfeld
    Conference: ACM SIGCOMM Internet-QoE 2017
    PDF DOI
  128. Internet-QoE'17
  129. How HTTP/2 Pushes the Web: An Empirical Study of HTTP/2 Server Push
    Torsten Zimmermann, Jan Rüth, Benedikt Wolters, Oliver Hohlfeld
    Conference: IFIP Networking Conference 2017
    PDF
  130. NETWORKING'17
  131. Veiled in Clouds? Assessing the Prevalence of Cloud Computing in the Email Landscape
    Martin Henze, Mary Peyton Sanford, Oliver Hohlfeld
    Conference: Network Traffic Measurement and Analysis Conference 2017
    PDF
  132. TMA'17
  133. Network Function Virtualization in Software Defined Infrastructures (Dagstuhl Seminar 17032)
    David Hausheer, Oliver Hohlfeld, Diego R. L{ó}pez, Bruce MacDowell Maggs, Costin Raiciu
    Journal: Dagstuhl Reports, Volume 7, pages 74--102 2017
    DOI
  134. Dagstuhl'17
  135. Performance Evaluation for New Web Caching Strategies Combining LRU with Score Based Object Selection
    Gerhard Hasslinger, Konstantinos Ntougias, Frank Hasslinger, Oliver Hohlfeld
    Journal: Elsevier Computer Networks, Volume 125, Issue 9, Oct, pages 172--186 2017
    PDF
  136. Comnet'17
  137. SymPerf: Predicting Network Function Performance
    Felix Rath, Johannes Krude, Jan R̈uth, Daniel Schemmel, Oliver Hohlfeld, Jo Agila Bitsch, Klaus Wehrle
    Conference: ACM SIGCOMM Poster 2017
    DOI
  138. '17

    2016

  139. Performance Evaluation for New Web Caching Strategies Combining LRU with Score Based Object Selection
    Gerhard Hasslinger, Konstantinos Ntougias, Frank Hasslinger, Oliver Hohlfeld
    Conference: International Teletraffic Congress 2016
    DOI
  140. ITC'16
  141. STEAN: A Storage and Transformation Engine for Advanced Networking Context
    Marc Werner, Johannes Schwandke, Matthias Hollick, Oliver Hohlfeld, Torsten Zimmermann, Klaus Wehrle
    Conference: IFIP NETWORKING 2016
    PDF
  142. NETWORKING'16
  143. ERWIN -- Enabling the Reproducible Investigation of Waiting Times for Arbitrary Workflows
    Matthias Hirth, Valentin Fischer Thomas Zinner, Oliver Hohlfeld
    Conference: IEEE Conference on Quality of Multimedia Experience 2016
    PDF
  144. QoMEX'16
  145. Moving Privacy-Sensitive Services from Public Clouds to Decentralized Private Clouds
    Martin Henze, Jens Hiller, Oliver Hohlfeld, Klaus Wehrle
    Conference: IEEE Workshop on Legal and Technical Issues in Cloud Computing and Cloud-Supported Internet of Things 2016
    PDF
  146. '16
  147. New Kid on the Block: Network Functions Virtualization: From Big Boxes to Carrier Clouds
    Leonhard Nobach, Oliver Hohlfeld, David Hausheer
    Journal: ACM SIGCOMM Computer Communication Review, Jul 2016
    PDF
  148. CCR'16
  149. Special issue on Software-Defined Networking and Network Functions Virtualization for flexible network management
    Oliver Hohlfeld, Thomas Zinner, Theophilus Benson, David Hausheer
    Journal: Wiley International Journal of Network Management, Volume 26, Issue 1, pages 4--5 2016
    DOI
  150. '16
  151. Insensitivity to Network Delay: Minecraft Gaming Experience of Casual Gamers
    Oliver Hohlfeld, Hannes Fiedler, Enric Pujol, Dennis Guse
    Conference: IEEE QCMan 2016
    PDF
  152. QCMan'16
  153. It's time to combine Network Advances and Databases
    Jens Helge Reelfs, Oliver Hohlfeld, Klaus Wehrle
    Conference: ACM CoNEXT Student Workshop 2016
  154. '16
  155. POSTER: I Don't Want That Content! On the Risks of the Exploitability of Bitcoin's Blockchain as a Content Store
    Roman Matzutt, Oliver Hohlfeld, Martin Henze, Robin Rawiel, Jan Henrik Ziegeldorf, Klaus Wehrle
    Conference: ACM CCS 2016
    PDF
  156. CCS Poster'16

    2015

  157. Annoyed Users: Ads and Ad-Block Usage in the Wild
    Enric Pujol, Oliver Hohlfeld, Anja Feldmann
    Conference: ACM Internet Measurement Conference 2015
    PDF
  158. IMC'15
  159. On the Applicability of Computer Vision based Gaze Tracking in Mobile Scenarios
    Oliver Hohlfeld, Andre Pomp, Jo Agila Bitsch Link, Dennis Guse
    Conference: ACM MobileHCI 2015
    PDF code
  160. MobileHCI'15
  161. Santa: Faster Packet Delivery for Commonly Wished Replies [Poster Abstract]
    Florian Schmidt, Oliver Hohlfeld, Rene Glebke, Klaus Wehrle
    Conference: ACM SIGCOMM Poster 2015
    PDF DOI
  162. SIGCOMM Poster'15
  163. Distributed Cloud Computing: Applications, Status Quo, and Challenges
    Yvonne Coady, Oliver Hohlfeld, James Kempf, Rick McGeer, Stefan Schmid
    Journal: ACM SIGCOMM Computer Communication Review, Volume 44, Apr 2015
    PDF DOI
  164. CCR'15
  165. Subjective Quality of Webpage Loading: The Impact of Delayed and Missing Elements
    Dennis Guse, Sebastian Schuck, Oliver Hohlfeld, Alexander Raake, Sebastian M̈oller
    Conference: IEEE Conference on Quality of Multimedia Experience 2015
    PDF
  166. QoMEX'15

    2014

  167. A QoE Perspective on Sizing Network Buffers
    Oliver Hohlfeld, Enric Pujol, Florin Ciucu, Anja Feldmann, Paul Barford
    Conference: ACM Internet Measurement Conference 2014
    PDF
  168. IMC'14
  169. On Capacity Dimensioning in Dynamic Scenarios: The Key Role of Peak Values
    Florin Ciucu, Felix Poloczek, Oliver Hohlfeld
    Conference: IEEE LANMAN 2014
    PDF
  170. LANMAN'14
  171. An Internet census taken by an illegal botnet - A qualitative assessment of published measurements
    Thomas Krenc, Oliver Hohlfeld, Anja Feldmann
    Journal: ACM SIGCOMM Computer Communication Review, Volume 44, jul 2014
    PDF
  172. CCR'14
  173. The Harvester, the Botmaster, and the Spammer: On the Relations Between the Different Actors in the Spam Landscape
    Gianluca Stringhini, Oliver Hohlfeld, Christopher Kruegel, Giovanni Vigna
    Conference: ACM Symposium on Information, Computer and Communications Security 2014
  174. AsiaCCS'14

    2013

  175. Impact of Buffering on User Experience
    Oliver Hohlfeld
    PhD Thesis TU Berlin 2013
    PDF
  176. PhD Thesis'13

    2012

  177. Longtime Behavior of Harvesting Spam Bots
    Oliver Hohlfeld, Thomas Graf, Florin Ciucu
    Conference: ACM Internet Measurement Conference 2012
    PDF
  178. IMC'12
  179. BufferBloat: How Relevant? A QoE Perspective on Buffer Sizing
    Oliver Hohlfeld, Enric Pujol, Florin Ciucu, Anja Feldmann, Paul Barford
    TechReport: TU Berlin, Fak. IV 2012
    PDF
  180. TechRep'12

    2011

  181. On the Convergence to Fairness in Overloaded FIFO Systems
    Florin Ciucu, Oliver Hohlfeld, Lydia Y. Chen
    Conference: IEEE INFOCOM 2011
    PDF
  182. INFOCOM'11
  183. On Revealing the ARQ Mechanism of MSTV
    Oliver Hohlfeld, Balamuhunthan Balarajah, Sebastian Benner, Alexander Raake, Florin Ciucu
    Conference: IEEE ICC 2011
    PDF
  184. ICC'11
  185. Analysis of Random and Burst Error Codes in 2-state Markov Channels
    Gerhard Hasslinger, Oliver Hohlfeld
    Conference: 34th International Conference on Telecommunications and Signal Processing 2011
    PDF DOI
  186. TSP'11

    2010

  187. Impact of Frame Rate and Resolution on Objective QoE Metrics
    Thomas Zinner, Ossama Abboud, Oliver Hohlfeld, Tobias Hossfeld
    Conference: QoMEX 2010
    PDF DOI
  188. QoMEX'10
  189. The Routerlab --- Emulating Internet Characteristics in a Room
    Amir Mehmood, Oliver Hohlfeld, Dan Levin, Andreas Wundsam, Florin Ciucu, Fabian Schneider, Anja Feldmann, Ralf-Peter Braun
    Conference: 11th ITG conference on photonic networks 2010
    PDF
  190. '10
  191. Efficiency of Caches for Content Distribution in the Internet
    Gerhard Hasslinger, Oliver Hohlfeld
    Conference: International Teletraffic Congress 2010
    PDF DOI
  192. ITC'10
  193. Non-Asymptotic Throughput and Delay Distributions in Multi-Hop Wireless Networks
    Florin Ciucu, Pan Hui, Oliver Hohlfeld
    Conference: 48th Annual Allerton Conference on Communication, Control, and Computing 2010
    PDF DOI
  194. Allerton'10
  195. Towards QoE Management for Scalable Video Streaming
    Thomas Zinner, Ossama Abboud, Oliver Hohlfeld, Tobias Hossfeld, Phuoc Tran-Gia
    Conference: 21st ITC Specialist Seminar on Multimedia Applications - Traffic, Performance and QoE 2010
    PDF
  196. ITC-SS'10
  197. On Computing Bounds on Average Backlogs and Delays with Network Calculus
    Florin Ciucu, Oliver Hohlfeld
    Conference: IEEE ICC 2010
    PDF DOI
  198. ICC'10

    2009

  199. Scaling of Buffer and Capacity Requirements of Voice Traffic in Packet Networks
    Florin Ciucu, Oliver Hohlfeld
    Conference: International Teletraffic Congress 2009
    PDF
  200. ITC'09
  201. Viewing Impaired Video Transmissions From a Modeling Perspective
    Oliver Hohlfeld, Florin Ciucu
    Journal: Performance Evaluation Review, Volume 37, sep, pages 33--35 2009
    PDF DOI
    [ Workshop on MAthematical Performance Modeling and Analysis (MAMA) at Sigmetrics ]
  202. SIGMETRICS MAMA'09
  203. Stochastic Packet Loss Model to Evaluate QoE Impairments
    Oliver Hohlfeld
    Journal: PIK, pages 53--56 2009
    PDF
  204. '09
  205. Stochastic Packet Loss Model to Evaluate QoE Impairments
    Oliver Hohlfeld
    Conference: KiVS: Master Thesis Award Session 2009
    PDF
  206. KiVS'09

    2008

  207. Packet Loss in Real-Time Services: Markovian Models Generating QoE Impairments
    Oliver Hohlfeld, Rüdiger Geib, Gerhard Haßlinger
    Conference: IEEE International Workshop on Quality of Service (IWQoS) 2008
    PDF DOI
  208. IWQoS'08
  209. The Gilbert-Elliott Model for Packet Loss in Real Time Services on the Internet
    Gerhard Haßlinger, Oliver Hohlfeld
    Conference: GI/ITG Conference on Measurement, Modeling, and Evaluation of Computer and Communication Systems (MMB) 2008
    PDF
    [ Errata ]
    Abstract: The estimation of quality for real-time services over telecommunication networks requires realistic models for impairments and failures during transmission. We focus on the classical Gilbert-Elliott model whose second order statistics is derived over arbitrary time scales and used to fit packet loss processes of traffic traces measured in the IP backbone of Deutsche Telekom. The results show that simple Markov models are appropriate to capture the observed loss pattern.
  210. MMB'08

    2005

  211. Instant Messaging Communication Gateway for Medical Applications
    Ilias Sachpazidis, Oliver Hohlfeld
    Conference: Proceedings of the IASTED International Conference on Telehealth 2005
    Abstract: Internet has changed the way of how people communicate and exchange information. Enduringly, more and more doctors are getting familiar with Internet and the offered capabilities. Hospitals are interconnected, making use of Internet, forming medical information networks. The doctors exchange information with the help of Internet. A very common way of communication is the electronic email even when a doctor looks for a second opinion from another expert doctor. In the market, various medical applications for tele-consultation can be found. Some of them are web based and others are stand alone applications. In this paper we will propose a communication gateway, based on Jabber instant messaging protocol, for modern and demanding medical applications, focusing on tele consultation applications. The proposed gateway is able to handle connections restricted by firewalls and makes use of potential available proxies inside of a network. In addition, we will address the problems related to firewalls and proxies and will proposed a new way of communication for medical applications based on Jabber an instant messaging protocol. Furthermore, in order to handle binary data transmission to an offline entity over a Jabber network, we proposed an extension to In-Band Byte streams communication protocol.
  212. '05
  213. Implementation of a Jabber-Based Medical Tele-Consulting Application
    Ilias Sachpazidis, Oliver Hohlfeld
    Conference: 5th International Network Conference (INC) 2005
  214. '05

Theses

PhD Thesis (2013)

Impact of Buffering on Quality of Experience

Technische Universität Berlin, 2013

Advisor: Anja Feldmann Dissertation Committee:

PDF Abstract / TU Berlin Metadata

Master Thesis (2008)

Statistical Error Model to Impair an H.264 Decoder

Technische Universität Darmstadt, 2008

I received the KuVS Master Thesis Award for the best master thesis in this area at the KiVS conference 2009. I also received a Master Thesis Award at MMB 2010.

PDF Abstract

Bachelor Thesis (2006)

Development of a instant messaging-based communication module for telemedical applications

University of Applied Sciences Darmstadt

Abstract

Hohlfeld, Oliver: Development of an Instant Messaging-based Communication Module for Telemedical Applications. In: Computer Graphic Topics, 17 (4), 2005, p. 43

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Oliver Hohlfeld
Brandenburg University of Technology
Chair of Computer Networks
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