Author Archives: Steve Uhlig

The October 2026 Issue

This October 2026 issue contains five papers.

The technical paper, IPv6 Hitlist Service: Lessons Learned From 10 Years of Operation, by Oliver Gasser, Lion Steger, Patrick Sattler, and Johannes Zirngibl offers a retrospective on 10 years of operating the IPv6 Hitlist Service, a popular resource for IPv6 measurement. The paper discusses technical changes to the service
over time, a coverage analysis comparing the hitlist to flow data from an ISP and Tier-1 network, results from a user survey, and a set of best practice recommendations.

The technical paper, A Multi-Dimensional Analysis of Broadband Performance at Community Anchor Institutions, by Jiayi Liu, David Choffnes, Alexander Gamero-Garrido, Michael Wasser, and Elizabeth Belding presents the results from a large-scale study of broadband performance and stability at Community Anchor Institutions (CAIs), e.g., libraries, schools and community centers. The authors find significant differences in performance between urban and rural CAIs, indicating that broadband inequality remains a persist problem.

In the editorial, AIMS 2026 Workshop Report, kc claffy presents a summary of the 19th Workshop on Active Internet Measurements (AIMS-19) held at the Center for Applied Internet Data Analysis
(CAIDA) at UC San Diego.

The editorial paper, From SRM to NDN: Lessons on Data-Centric Communication from Three Decades of Networking, by Tianyuan Yu, Adam Thieme, Junxiao Shi, Lan Wang, and Lixia Zhang presents a restrospective view of 30-year old work on scalable-and-reliable-multicast (SRM). The paper argues that reliable multicast can be achieved more effectively by means of the basic, network-level communication mechanisms of Named Data Networking (NDN), and that NDN is a better network architecture for group communication than traditional TCP/IP. To paraphrase the reviewers, these unorthodox ideas deserve to be heard.

In Unknown Is Not False: On Negative Results and the Limits of Inference, Fabián E. Bustamante presents an editorial based on his keynote presentation at the 2026 ACM Workshop on Negative Results in Network Measurements (NetNeg). In this thought-provoking article, the author argues that having insufficient evidence to validate a hypothesis can itself be a meaningful scientific result.

I hope that you will enjoy reading this new issue.

The July 2026 Issue

This July 2026 issue contains three technical papers.

The first paper, The Carrier Pigeon Internet Protocol: An Algorithmic (and Lighthearted) Perspective by Matthias Bentert, Shay Kutten, Darya Melnyk, Tijana Milentijević,, and Stefan Schmid is an amusing read that investigates protocols and complexities of communication networks based on carrier pigeons. While lighthearted in nature, the paper is technically grounded in classic mathematical techniques used to analyze modern computer networks. This creative paper is both entertaining and informative—in fact, the paper proposes follow-up work that I’d love to see.

The second paper, A DualPI2 Module for Mahimahi: Behavioral Characterization and Cross-Platform Analysis by Nawel Alioua, Linghe Zhang, Aneesh Garg, Francis Y. Yan, and Elizabeth Belding describes the development of a modular implementation of the DualPI2 active queue management logic integrated into the Mahimahi network emulator. The authors use the DualPI2 module to analyze Low Latency, Low Loss, and Scalable Throughput (L4S) protocol and congestion control technologies, comparing the emulated results with real execution in the kernel. The artifacts should be useful to other researchers in the L4S space.

The third paper, From robots.txt to ai.txt: Mapping the Evolution of Web Permissions in the Age of AI by Felix Hoffmann, Tobias Goergens, Sonal Khosla, and Vaibhav Bajpai presents a measurement study that attempts to quantify the adoption of AI-oriented policy and descriptor files (e.g., (ai.txt, llms.txt, llms-full.txt) and analyze their use. The paper provides a useful analysis for understanding how website operators are responding to AI-driven crawling.

I hope that you will enjoy reading this new issue.

The April 2026 Issue

This April 2026 issue contains one technical paper and one editorial paper.

The technical paper, When the Lights Go Out: Internet Resilience During the 2025 Iberian Power Outage, by Oliver Hohlfeld, Yasin Alhamwy, Tobias Striffler, Daniel Wagner, and Matthias Wichtlhuber studies the impact of a major power outage in Spain and Portugal on the region’s Internet connectivity. Through an extensive, data-driven analysis, the authors provide insights on how the loss of electricity affects both end-users and core network infrastructure. This study will help inform the design of resiliency strategies to guard against future, similar disruptions.

The second paper, an editorial, An Experience Report on Artifact Evaluation in Brazilian Conferences, by Tiago Heinrich, Diego Kreutz, Roben Lunardi, Rodrigo Mansilha, Vinicius Fulber-Garcia, Lourenco A. Pereira, and Rafael R. Obelheiro describes the process for conducting artifact evaluation at conferences in Brazil. The authors provide insights into the challenges they faced and the solutions they adopted to address them. This editorial will not only help conference organizers facing similar challenges, but also provide more insight to authors
about the evaluation process.

I hope that you will enjoy reading this new issue and welcome comments and suggestions on CCR Online or by email at ccr-editor@sigcomm.org.

TelecomRAG: Taming Telecom Standards with Retrieval Augmented Generation and LLMs

Girma M. Yilma, Jose A. Ayala-Romero, Andres Garcia-Saavedra, Xavier Costa-Perez

Abstract

Large Language Models (LLMs) have immense potential to transform the telecommunications industry. They could help professionals understand complex standards, generate code, and accelerate development. However, traditional LLMs struggle with the precision and source verification essential for telecom work. To address this, specialized LLM-based solutions tailored to telecommunication standards are needed. This Editorial Note showcases how Retrieval-Augmented Generation (RAG) can offer a way to create precise, factual answers. In particular, we show how to build a Telecommunication Standards Assistant that provides accurate, detailed, and verifiable responses. We show a usage example of this framework using 3GPP Release 16 and Release 18 specification documents. We believe that the application of RAG can bring significant value to the telecommunications field.

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Towards Immersive Cloud-Based IoT Education

Fan Gabriella Xue, Matthew Caesar

Abstract

An increasing number of students are becoming interested in learning about the Internet of Things (IoT) space. However, today, we lack scalable and efficient ways to bring hands-on IoT learning to many due to hardware accessibility, system complexity, and deployment environment constraints. This paper presents ThingVisor, an IoT learning platform that enables hands-on IoT development in an immersive virtual space. Specifically, it allows users to design, test, and deploy IoT devices virtually in a simulated IoT world with static and dynamic software verification as a complementary tool to IoT education. ThingVisor consists of (1) a Device Design Stack to configure virtual IoT devices, (2) an Immersive Runtime Stack to interact with devices and environment, and (3) a Device Emulator, which is a runtime environment used to execute virtual devices to get their behaviors. Our experiments confirm the learning effectiveness and user satisfaction of our platform. Additionally, we have demonstrated the scalability and usability of the system through load testing and application of the System Usability Scale. Our results indicate that students can achieve up to a 32% improvement in their scores after engaging with ThingVisor for two weeks, irrespective of their prior experience.

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A Survey on Packet Filtering

Nik Sultana, Hyunsuk Bang, Elena Yulaeva, Ricky K. P. Mok, Kc Claffy, Richard Mortier

Abstract

Packet filtering has remained a key network monitoring primitive over decades, even as networking has continuously evolved. In this article we present the results of a survey we ran to collect data from the networking community, including researchers and practitioners, about how packet filtering is used. In doing so, we identify pain points related to packet filtering, and unmet needs of survey participants. Based on analysis of this survey data, we propose future research and development goals that would support the networking community.

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The July 2024 issue

This July 2024 issue contains one technical paper, one educational paper, and one editorial note.

The technical paper, A Survey on Packet Filtering, by Nick Sultana and colleagues, was originally submitted as an editorial. Given that CCR does not usually consider survey papers, it went through a thorough reviewing process. Given its value to the community, we felt that it deserves to be accepted as a technical paper, not an editorial. The topic of this work is important to the community, namely packet filtering. The authors present the results of a survey they ran to collect data from the networking community, including researchers and practitioners, about how packet filtering is used. They identify pain points related to packet filtering, and unmet needs of survey participants. Based on analysis of this survey data, they propose future research and development goals that would support the networking community.

The second paper, an educational contribution, Towards Immersive Cloud-Based IoT Education, by Fan Gabriella Xue and Matthew Caesar, presents ThingVisor, an IoT learning platform that enables hands-on IoT development in an immersive virtual space. Specifically, it allows users to design, test, and deploy IoT devices virtually in a simulated IoT world with static and dynamic software verification as a complementary tool to IoT education. The experiments confirm the learning effectiveness and user satisfaction of the platform, as well as the scalability and usability of the system.

Finally, the editorial note, TelecomRAG: Taming Telecom Standards with Retrieval Augmented Generation and LLMs by Girma M. Yilma and colleagues, discusses the very timely topic of Large Language Models (LLMs), and discuss the potential they have in transforming the telecommunications industry.

I hope that you will enjoy reading this new issue and welcome comments and suggestions on CCR Online (https://ccronline.sigcomm.org) or by email at ccr-editor at sigcomm.org.

Towards Re-Architecting Today’s Internet for Survivability: NSF Workshop Report

Fabián E. Bustamante, John Doyle, Walter Willinger, Marwan Fayed, David L. Alderson, Steven Low, Stefan Savage, Henning Schulzrinne

Abstract

On November 28–29, 2023, Northwestern University hosted a workshop titled “Towards Re-architecting Today’s Internet for Survivability” in Evanston, Illinois, US. The goal of the workshop was to bring together a group of national and international experts to sketch and start implementing a transformative research agenda for solving one of our community’s most challenging yet important tasks: the re-architecting of tomorrow’s Internet for “survivability”, ensuring that the network is able to fulfill its mission even in the presence of large-scale catastrophic events. This report provides a necessarily brief overview of two full days of active discussions.

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On Sample Selection for Continual Learning: A Video Streaming Case Study

Alexander Dietmüller, Romain Jacob, Laurent Vanbever

Abstract

Machine learning (ML) is a powerful tool to model the complexity of communication networks. As networks evolve, we cannot only train once and deploy. Retraining models, known as continual learning, is necessary. Yet, to date, there is no established methodology to answer the key questions: With which samples to retrain? When should we retrain?
We address these questions with the sample selection system Memento, which maintains a training set with the “most useful” samples to maximize sample space coverage. Memento particularly benefits rare patterns—the notoriously long “tail” in networking—and allows assessing rationally when retraining may help, i.e., when the coverage changes.
We deployed Memento on Puffer, the live-TV streaming project, and achieved a 14 % reduction of stall time, 3.5× the improvement of random sample selection. Memento is model-agnostic and can be applied beyond video streaming.

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The April 2024 issue

This April 2024 issue contains two technical papers and one editorial note.

The first technical paper, This Is a Local Domain: On Amassing Country-Code Top-Level Domains from Public Data, by Raffaele Sommese and colleagues, presents a measurement study that investigates ccTLD coverage using public data sources. Domain lists such as Alexa and Tranco are crucial tools for performing representative Web censuses. However, these lists often overlook domains under country-code top-level domains (ccTLDs), resulting in biased census outcomes. The authors demonstrate that data from Certificate Transparency (CT) logs and Common Crawl provide robust ccTLD coverage and can serve as reliable proxies for Web censuses. The authors also plan to release ccTLD domain names to the community as part of an expansion of the daily OpenINTEL measurement.

The second technical paper, On Sample Selection for Continual Learning: a Video Streaming Case Study, by Alexander Dietmüller and colleagues, proposes Memento, a prototype implementation aiming at improving sample selection, especially in the tail of the traffic distribution. An already sizable and increasing body of work focuses on using ML models to capture the inherent complexity of communication networks. And yet, as network traffic evolves, ML approaches need to tackle the issue of concept drift, which implies that the model will eventually underperform. This means that ML models need retraining. When to retrain and on what data remain difficult problems. This paper focuses precisely on those open issues.

Finally, the editorial note, Towards Re-architecting Today’s Internet for Survivability — NSF Workshop Report by Fabian Bustamante and colleagues, reports on a workshop that took place on November 28-29, 2023, at Northwestern University. The goal of the workshop was to bring together a group of national and international experts to sketch and start implementing a transformative research agenda for solving one of our community’s most challenging yet important tasks: the re-architecting of tomorrow’s Internet for “survivability”, ensuring that the network is able to fulfill its mission even in the presence of large-scale catastrophic events.

I hope that you will enjoy reading this new issue and welcome comments and suggestions on CCR Online (https://ccronline.sigcomm.org) or by email at ccr-editor at sigcomm.org.