The July 2022 issue

This July 2022 issue contains one technical paper and two editorial notes.

The technical paper, The Packet Number Space Debate in Multipath QUIC, by Quentin De Coninck, deals with how QUIC packets should be numbered over multiple paths. This work provides a comparison between the usage of a single (shared) or multiple packet space numbers for QUIC multipath. The main outcome of the evaluation is that using multiple packet number spaces has the advantage that packet losses can be detected while maintaining a significantly lower state at the receiver. Also, it allows using fewer signalling frames at the cost of a more profound modification of the QUIC protocol.

We have two editorial notes. The first one, The multiple roles that IPv6 addresses can play in today’s Internet, by Maxime Piraux and his colleagues, argues that the large IPv6 addressing space allows reconsidering how IP addresses are used and enables improving, simplifying and scaling the Internet. The second, AppClassNet: A commercial-grade dataset for application identification research by Wang Chao and his colleagues, releases a commercial-grade dataset for benchmarking traffic classification and management methodologies. AppClassNet is significantly larger than the datasets generally available to the academic community.

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

The April 2022 issue

This April 2022 issue contains five technical papers and two editorial notes.

The first technical paper, Data-Plane Security Applications in Adversarial Settings, by Liang Wang and colleagues, investigates security issues that may arise when creating and running data-plane applications for programmable switches. This work moves security analysis and design forward in this particular area. This paper also calls for a more thorough rethinking of security for data-plane applications for programmable switches.

The second technical paper, One Bad Apple Can Spoil Your IPv6 Privacy, by Said Jawad Saidi and colleagues, leverages IPv6 passive measurements to pinpoint that a non-negligible portion of devices encodes their MAC address in their IPv6 address. This threatens users’ privacy, allowing content providers and CDNs to consistently track users and their devices across multiple sessions and locations. Overall, the paper is an excellent contribution toward privacy-by-design solutions and a nicely executed measurements study that clarifies the problem and provides solid suggestions to mitigate the problem.

The third technical paper, Hyper-Specific Prefixes: Gotta Enjoy the Little Things in Interdomain Routing, by Khwaja Zubair Sediqi and colleagues, investigates the presence of high-specific prefixes (HSP) on the BGP Internet routing during the last decade. These prefixes are more-specific than /24 (/48) for IPv4 (IPv6) and are commonly filtered by Autonomous Systems operators. Overall this paper offers a nice contribution to the understanding of the BGP universe, with a clear message and a nice quantification of the phenomenon. The authors clearly present and motivate the work, offering also to not experts a nice view of the routing complexity of the internet nowadays.

The fourth technical paper, Programming Socket-Independent Network Functions with Nethuns, by Nicola Bonelli and colleagues, proposes a new solution to transparently develop packet-processing programs on top of different network I/O frameworks. The authors design and develop an open-source library, nethuns, serving as a unified programming abstraction for network functions that natively supports multi-core programming. Not only is this work very relevant to our community, but also the code is released open-source through a BSD license, which can be used to foster more research in the area, towards unifying programming mechanisms of end-host networking.

The fifth technical paper, Measuring DNS over TCP in the Era of Increasing DNS Response Sizes: A View from the Edge, by Mike Kosek and colleagues, studies one of the foundations of today’s Internet: the Domain Name Service (DNS). The original RFC document of DNS instructs to send queries either over UDP (DoUDP) or TCP (DoTCP). This paper presents a measurement study on DoTCP focusing on two perspectives: failure rates and response times.

Finally, we have two editorial notes. A Case for an Open Customizable Cloud Network, by Dean H. Lorenz and his colleagues, argues for the desirability of the new ecosystem of managed network solutions to connect to the Cloud, outlines the main requirements and sketches possible solutions. Recommendations for Designing Hybrid Conferences, by Vaibhav Bajpai and colleagues, presents guidelines and considerations–spanning technology, organization and social factors–for organizing successful hybrid conferences.

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

The January 2022 issue

This January 2022 issue contains three technical papers and four editorial notes.

The first technical paper, Zeph & Iris Map the Internet – A resilient reinforcement learning approach to distributed IP route tracing, by Matthieu Gouel and colleagues, proposes to improve topology discovery by optimizing the use of existing probing resources. This can be done by intelligently allocating probing directives to vantage points. The system is based on the inter-working of two components: Iris, which takes care of the route tracing, and Zeph, which coordinates Iris’s measurements. The results in the paper show that Zeph, in combination with Iris, are able to facilitate fast topology measurements from geographically distributed vantage points.

The second technical paper, Towards Retina-Quality VR Video Streaming: 15ms Could Save You 80\% of Your Bandwidth, by Luke Hsiao and colleagues, investigates how to provide retina-quality video streaming in virtual reality (VR). The paper studies the impact of the motion-to-photon latency — the time between a change in the viewer’s gaze and the resulting change in the display’s pixels — on a VR system. This metric is paramount for VR systems since it impacts video compression. The paper shows, experimentally, that a client and streaming server system with sub-15 ms end-to-end motion-to-photon latency benefit from 5x better video compression than in presence of larger latencies. The paper also shows how to build such a low latency system both hardware and software-wise.

The third technical paper, Towards client-side active measurements without application control, by Palak Goenka and colleagues, proposes to harness Network Error Logging (NEL) to enable active client-side measurements (RTT and connection availability) by dynamically modifying the HTTPS endpoint where NEL reports should be uploaded. Network Error Logging (NEL) is a W3C standard which defines how web servers can receive from a browser reports about performance and failures of web requests. The techniques used in the paper enable active client-side measurements in the browser without requiring Javascript code injection, which is the current and more invasive state of the art solution.

Finally, we have four editorial notes. Roadmap for Edge AI: A Dagstuhl Perspective, by Aaron Yi Ding and his colleagues, based on the collective input of Dagstuhl Seminar (21342), presents a comprehensive discussion on AI methods and capabilities in the context of edge computing, referred as Edge AI. Then, M-Lab: User initiated Internet data for the research community, by Phillipa Gill and her colleagues, presents Measurement Lab (M-Lab), an open, distributed server platform on which researchers have deployed measurement tools. Important Concepts in Data Communications, by Craig Partridge, presents one perspective about which concepts or ideas in data communications have proven to be enduring in the evolution of data communications. Finally, Answering Three Questions About Networking Research, by Jennifer Rexford and Scott Shenker, presents the first of a series of answers to three questions that were asked to panelists during HotNets’21, about how they pick their own research topics, what areas they would like to see more research on, and how they evaluate conference papers.

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

The October 2021 issue

This October 2021 issue contains two technical papers, two educational contributions, and one editorial note.

The first technical paper, When Latency Matters: Measurements and Lessons Learned, by Marco Iorio and colleagues, evaluates the “latency argument” for edge computing, i.e., that placing elastic computing and storage platforms in close proximity to end-users makes sense for latency-critical applications. The paper evaluates several sources of latency, including latency induced by core network routing inefficiencies, wired and wireless access network, transport protocol and application protocol. The paper concludes that moving data-centers close to the users is only a small part of the latency problems, and that solving it requires a more careful coordination of efforts across the network stack.

The second technical paper, REDACT: Refraction Networking from the Data Center, by Arjun Devraj and colleagues, extends the concept of refraction networking by assigning the edge router of a cloud datacenter the role of a decoy router.

The first educational contribution, Machine learning-based Analysis of COVID-19 Pandemic Impact on US Research Networks, by Mariam Kiran and colleagues, sheds light on the performance of a large network throughout the COVID-19 pandemic. Extensive traces are studied and analyzed, with a number of interesting findings using various statistical techniques.

The second educational contribution, An educational toolkit for teaching cloud computing, by Cosimo Anglano and colleagues, proposes the creation of a software layer to hide the specifics of the underlying cloud platforms from students, enabling them to perform their assignments atop a general API. The proposed approach is an innovative idea to improve the educational experience of students on cloud platforms.

Finally, we have an editorial note. Data-driven Networking Research: models for academic collaboration with industry (a Google point of view), by Jeffrey C. Mogul and his colleagues, describes collaboration models aimed at stimulating data-driven networking research. The authors describe specific areas where they would welcome proposals to work within those models.

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

The July 2021 issue

This July 2021 issue contains one technical paper, two educational contributions, as well as four editorial notes.

The technical paper, NemFi: Record-and-replay to emulate WiFi, by Abhishek kumar Mishra and colleagues, proposes a trace-driven WiFi emulator called NemFi, that allows modeling of transmission opportunities of uplink and downlink directions, packet loss, frame aggregation, and media access control behavior. The latter two concepts are unique for WiFi when compared with other similar tools that have been built for cellular networks.

The first educational contribution, The Graph Neural Networking Challenge: A Worldwide Competition for Education in AI/ML for Networks, by Jose Suarez-Varela and colleagues, proposes a ”challenge” to teach students about applications of AI/MLin computer networks. The authors describe a process to select a dataset, and a competition-based approach where participants must design a neural-network-based approach to infer properties of the dataset with as much accuracy as possible.

The second educational contribution, P4Pi: P4 on Raspberry Pi for Networking Education, by Sandor Laki and colleagues, presents a novel platform for networking education based on a Raspberry Pi, allowing students to program P4.

Then, we have four editorial notes. The first one, Limited Domains Considered Useful, by Brian Carpenter and his colleagues, argues not only that limited domains have been with us from the very beginning of the Internet but also that they have been shaping innovation of Internet technologies ever since, and will continue to do so.

The second editorial note, Collaboration in the IETF: An Initial Analysis of Two Decades in Email Discussions, by Michael Welzl and his colleagues, discusses the following question: when big players follow such a “shoot first, discuss later” approach, is IETF collaboration still “real”, or is the IETF now being (mis-)used to approve protocols for standardization when they are already practically established, without really actively involving anyone but the main proponents?

The third editorial note, Workshop on Overcoming Measurement Barriers to Internet Research (WOMBIR 2021) Final Report, by kc claffy and her colleagues, reports on the Workshop on Overcoming Measurement Barriers to Internet Research (WOMBIR), held earlier in 2021.

The fourth and last editorial note, A Square Law Revisited, by Brian Carpenter, revisits the approximate apparent growth of the globally addressable Internet in proportion to the square root of the host count.

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

The April 2021 issue

The April 2021 issue contains one technical paper as well as five editorial notes.

The technical paper, Surviving switch failures in cloud datacenters, by Rachee Singh and her colleagues, examines the nature of switch failures in the datacenters of a large commercial cloud provider. This work studies a cohort of over 180,000 switches with a variety of hardware and software configurations.

Then, we have five editorial notes. The first one, The Netivus Manifesto: Making Collaborative Network Management Easier for the Rest of Us, by Joseph Severini and his colleagues, studies operational issues faced by Small and Medium Enterprise (SME) network owners.

The second editorial note, Revitalizing the Public Internet By Making it Extensible, by Hari Balakrishnan and his colleagues, argues for the creation of an Extensible Internet that supports in-network services that go beyond best-effort packet delivery.

The third editorial note, Workshop on Internet Economics (WIE 2020) Final Report, by kc claffy and David Clark, reports on the 11th interdisciplinary Workshop on Internet Economics (WIE).

The fourth editorial note, SatNetLab: A call to arms for the next global Internet testbed, by Ankit Singla, lays out a case for networking researchers to collaboratively undertake the construction of SatNetLab, a research platform that enables experimentation across upcoming satellite-based networks.

The fifth editorial note, Great Educators in Computer Networking: Bruce Davie, by Matthew Caesar and Bruce Davie, is an interview, part of a series on Great Educators in Computer Networking, where some of the most impactful and skilled educators in our field are interviewed.

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

The January 2021 issue

This January 2021 issue contains three technical papers as well as two editorial notes.

The first technical paper, Distrinet: a Mininet Implementation for the Cloud, by Giuseppe Di Lena and his colleagues, proposes Distrinet, a distributed implementation of Mininet over multiple hosts, based on LXD/LXC, Ansible, and VXLAN tunnels. Distrinet is compatible with Mininet programs, generic and can deploy experiments on Linux clusters as well as on the Amazon EC2 cloud platform. Given how popular Mininet is for SDN evaluation, this contribution potentially provides a lot of value to our research community.

The second technical paper, Experience-Driven Research on Programmable Networks, by Hyojoon Kim and colleagues, presents a proof-of-concept to help researchers run experiments against their programmable network idea, in their own network. The authors present several data-plane applications as use cases that run on their campus and solve production network problems. While not fully reproducible, this paper is a good step towards encouraging similar efforts in our community.

Our third paper, The Case for Model-Driven Interpretability of Delay-based Congestion Control Protocols, by Muhammad Khan and his colleagues, presents a study of different delay-based congestion control algorithms for TCP. The proposed framework is flexible and allows to model delay-based protocols, by simplifying a congestion control protocol’s response into a guided random walk over a two-dimensional Markov model. The model is evaluated against actual traces collected in 3G/4G networks, and allows to get the intuition of which regime the congestion control loop is spending most of the time.

Then, we have two editorial notes. The first one, Italian Operators’ Response to the COVID-19 Pandemic, by Massimo Candela and Antonio Prado, reports on the actions undertaken by network operators in Italy in response to COVID-19. The second editorial note, What do Information Centric Networks, Trusted Execution Environments, and Digital Watermarking have to do with Privacy, the Data Economy, and their future?, by Nikolaos Laoutaris and Costas Iordanou, discusses how ICNs combined with trusted execution environments and digital watermarking can be combined to build a personal data overlay inter-network that has a plethora of desirable properties for end-users.

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

The October 2020 issue

This October 2020 issue contains five technical papers, the third paper of our education series, as well as three editorial notes.

The first technical paper, Partitioning the Internet using Anycast Catchments, by Kyle Schomp and Rami Al-Dalky, deals with anycast, one of the core operational strategies to improve service performance, availability and resilience. Anycast is widely used by cloud providers, content delivery networks (CDNs), major DNS operators and many more popular Internet services. However, anycast comes with limited visibility in how traffic will be distributed among the different server locations. The authors of this paper paper propose a technique for partitioning the Internet using passive measurements of existing anycast deployments, such that all IP addresses within a partition are routed to the same location for an arbitrary anycast deployment.

The second technical paper, LoRadar: LoRa Sensor Network Monitoring through Passive Packet Sniffing, by Kwon Nung Choi and colleagues, moves us to a very different topic, in the area of IoT, and in particular Low Power WAN technologies (LPWANs) such as Long Range (LoRa). This paper develops a software tool, LoRadar, to monitor LoRa’s medium access control protocol on commodity hardware via passive packet sniffing.

Our third paper, A first look at the IP eXchange Ecosystem, by Andra Lutu and her colleagues, deals with the very important topic of the IPX Network, which we use every time we roam with our smartphones and interconnects about 800 Mobile Network Operators (MNOs) worldwide. Despite its size, neither its organisation nor its operation are well known within our community. This paper provides a first analysis of the IPX network, which we hope will be followed by other works on this under-studied topic.

The fourth paper, Mobile Web Browsing Under Memory Pressure, by Ihsan Ayyub Qazi and colleagues, investigates the impact of memory usage on mobile devices in the context of web browsing. The authors present a study using landing page loading time and memory requirements for a number of Android-based smartphones using Chrome, Firefox, Microsoft Edge and Brave. The extensive results of this paper cover the effect of tabs, scrolling, the number of images, and the number of requests made for different objects.

The fifth paper, Retrofitting Post-Quantum Cryptography in Internet Protocols: A Case Study of DNSSEC, by Moritz Mueller and his colleagues, analyses the implications of different Post-Quantum Cryptography solutions in the context of Domain Name System Security Extensions. What makes this paper very interesting, is its timeliness, since the networking and security communities are currently investigating suitable alternatives for DNSSEC, and candidate solutions shall be selected by early 2022.

The sixth paper, also our third paper in the new education series, COSMOS Educational Toolkit: Using Experimental Wireless Networking to Enhance Middle/High School STEM Education, by Panagiotis Skrimponis and his colleagues, describes COSMOS, a general-purpose educational toolkit for teaching students about a variety of computer science concepts, including computer networking. The notable aspect of this work is that the COSMOS testbed has already been deployed and used by a large number of students, and has already demonstrated great value to the community.

Then, we have three editorial notes. The first two are coincidentally on the very timely topic of contact tracing. The first one, Coronavirus Contact Tracing: Evaluating The Potential Of Using Bluetooth Received Signal Strength For Proximity Detection, by Douglas J. Leith and Stephen Farrell, reports on the challenges faced when deploying Covid-19 contact tracing apps that use Bluetooth Low Energy (LE) to detect proximity. The second editorial note, Digital Contact Tracing: Technologies, Shortcomings, and the Path Forward, by Amee Trivedi and Deepak Vasisht, investigates the technology landscape of contact-tracing apps and reports on what they believe are the missing pieces. Our third and final editorial note, Using Deep Programmability to Put Network Owners in Control, by Nate Foster and colleagues, share their vision regarding deep programmability across the stack.

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

The July 2020 issue

This July 2020 issue contains four technical papers, the second paper of our education series, as well as two editorial notes.

The first technical paper, Tracking the deployment of TLS 1.3 on the Web: A story of experimentation and centralization, by Ralph Holz and his colleagues, deals with Transport Layer Security (TLS) 1.3, a redesign of the Web’s most important security protocol. TLS 1.3 was standardized in August 2018 after a four year-long, unprecedented design process involving many cryptographers and industry stakeholders. In their work, the authors track deployment, uptake, and use of TLS 1.3 from the early design phase until well over a year after standardization.

The second technical paper, Does Domain Name Encryption Increase Users’ Privacy?, by Martino Trevisan and colleagues, is on a topic related to the first technical paper. This work shows that DNS over HTTP (DoH) does not offer the privacy protection that many assume. For the purposes of reproducibility, the authors provide the data used under NDA with the institution owning the data. The authors also share config files and ML environment details in the interest of promoting replicability in other environments.

Our third paper, Using Application Layer Banner Data to Automatically Identify IoT Devices, by Talha Javed and his colleagues, is of the “repeatable technical papers” type, which are technical contributions that provide their artefacts, e.g., software, datasets. This paper attempts to replicate a Usenix Security 2018 paper. It describes the efforts of the authors at re-implementing the solution described in the Usenix Security paper, especially the challenges encountered when authors of the original paper are unwilling to respond to requests for artefacts. We hope it will encourage additional reproducibility studies.

The fourth paper, Towards Declarative Self-Adapting Buffer Management, by Pavel Chuprikov and his colleagues, introduces a novel machine learning based approach to buffer management. The idea is to provide a queue management infrastructure that automatically adapts to traffic changes and identifies the policy that is hypothetically best suited for current traffic patterns. The authors adopt a multi-armed bandits model, and given that different objectives and assumptions lead to different bandit algorithms, they discuss and explore the design space while providing an experimental evaluation that validates their recommendations. The authors provide a GitHub repository that allows for the reproducibility of their result through the NS-2 simulator.

The fifth paper, also our second paper in the new education series, Open Educational Resources for Computer Networking, by Olivier Bonaventure and his colleagues, describes an effort to create an online, interactive textbook for computer networking. What distinguishes this textbook from traditional ones is that it not only is it free and available for anyone in the world to use, but also, it is also interactive. Therefore, this goes way beyond what a textbook usually offers: it is an interactive learning platform for computer networking. The authors here report on about ten years of experience with it, that led to some interesting experiences and lessons learned.

Then, we have two editorial notes. The first, Lessons Learned Organizing the PAM 2020 Virtual Conference, by Chris Misa and his colleagues, reports on the experience from the organizing committee of the 2020 edition of the Passive and Active Measurement (PAM) conference, that took place as a virtual event. It provides important lessons learned for future conferences that decide to go for a virtual event. The second editorial note, Update on ACM SIGCOMM CCR reviewing process: making the review process more open, by the whole CCR editorial board, aims to inform the SIGCOMM community on the reviewing process in place currently at CCR, and to share our plans to make CCR a more open and welcoming venue, adding more value to the SIGCOMM community.

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

The April 2020 Issue

SIGCOMM Computer Communication Review (CCR) is produced by a group of members of our community that spend time to prepare the newsletter that you read every quarter. Olivier Bonaventure served as editor during the last four years and his term is now over. It is my pleasure to now serve the community as the editor of CCR. As Olivier and other editors in the past did, we’ll probably adjust the newsletter to the evolving needs of the community. A first change is the introduction of a new Education series led by Matthew Caesar, our new SIGCOMM Education Director. This series will be part of every issue of CCR, and will contain different types of contributions, not only technical papers as in the current issue, but also position papers (that promote discussion through a defensible opinion on a topic), studies (describing research questions, methods, and results), experience reports (that describe an approach with a reflection on why it did/did not work), and approach reports (that describe a technical approach with enough detail for adoption by others).

This April 2020 issue contains five technical papers, the first paper of our new education series, as well as three editorial notes.

The first technical paper, RIPE IPmap Active Geolocation: Mechanism and Performance Evaluation, by Ben Du and his colleagues, introduces the research community to the IPmap single-radius engine and evaluates its effectiveness against commercial geolocation databases.

It is often believed that traffic engineering changes are rather infrequent. In the second paper, Path Persistence in the Cloud: A Study of the Effects of Inter-Region Traffic Engineering in a Large Cloud Provider’s Network, Waleed Reda and his colleagues reveal the high frequency of traffic engineering activity within a large cloud provider’s network.

In the third paper, The Web is Still Small After More Than a Decade, Nguyen Phong Hoang and his colleagues revisit some of the decade-old studies on web presence and co-location.

The fourth paper, a repeatable paper originated in the IMC reproducibility track, An Artifact Evaluation of NDP, by Noa Zilberman, provides an analysis of NDP (New Data centre protocol). NDP was first presented at ACM SIGCOMM 2017 (best paper award) and proposes a novel data centre transport architecture. In this paper, the author builds the analysis of the artefact proposed by the original authors of NDP, showing how it is possible to carry out research and build new results on previous work done by other fellow researchers.

The Low Latency, Low Loss, Scalable throughput (L4S) architecture addresses this problem by combining scalable congestion control such as DCTCP and TCP Prague with early congestion signalling from the network. In our fifth technical paper, Validating the Sharing Behavior and Latency Characteristics of the L4S Architecture, Dejene Boru Oljira and his colleagues validate some of the experimental result(s) reported in the previous works that demonstrate the co-existence of scalable and classic congestion controls and its low-latency service.

The sixth paper, also our very first paper in the new education series, An Open Platform to Teach How the Internet Practically Works, by Thomas Holterbach and his colleagues, describes a software infrastructure that can be used to teach about how the Internet works. The platform presented by the authors aims to be a much smaller, yet a representative copy of the Internet. The paper’s description and evaluation are focused on technical aspects of the design, but as a teaching tool, it may be more helpful to describe more about pedagogical issues.

Then, we have three very different editorial notes. The first, Workshop on Internet Economics (WIE 2019) report, by kc Klaffy and David Clark, reports on the 2019 interdisciplinary Workshop on Internet Economics (WIE). The second, strongly related to the fourth technical paper, deals with reproducibility. In Thoughts about Artifact Badging, Noa Zilberman and Andrew Moore illustrate that the current badging scheme may not identify limitations of architecture, implementation, or evaluation. Our last editorial note is a comment on a past editorial, “Datacenter Congestion Control: Identifying what is essential and making it practical” by Aisha Mushtaq, et al., from our July 2019 issue. This comment, authored by James Roberts, disputes that shortest remaining processing time (SRPT the crucial factor in achieving good flow completion time (FCT) performance in datacenter networks.

Steve Uhlig — CCR Editor

AppClassNet: A commercial-grade dataset for application identification research

Wang Chao, Alessandro Finamore, Lixuan Yang, Kevin Fauvel, Dario Rossi


The recent success of Artificial Intelligence (AI) is rooted into several concomitant factors, namely theoretical progress coupled to practical availability of data and computing power. Therefore, it is not surprising that the lack of high quality data is often recognized as one of the major factors limiting AI research in several domains, and the networking domain is not excluded. Large companies have access to large data assets, that would constitute interesting benchmarks for algorithmic research in the broader scientific community. However, such datasets are private assets that are generally very difficult to share due to privacy or business sensitivity concerns.

Following numerous requests we received from the scientific community, we release AppClassNet, a commercial-grade dataset for benchmarking traffic classification and management methodologies. AppClassNet is significantly larger than the datasets generally available to the academic community in terms of both the number of samples and classes, and reaches scales similar to the popular ImageNet dataset commonly used in computer vision literature.

To avoid leak of user- and business-sensitive information, we opportunely anonymized the dataset, while empirically showing that it still represents a relevant benchmark for algorithmic research. In this paper, we describe the public dataset as well as the steps we took to avoid leakage of sensitive information while retaining relevance as a benchmark. We hope that AppClassNet can be instrumental for other researchers to address more complex commercial-grade problems in the broad field of traffic classification and management.

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The multiple roles that IPv6 addresses can play in today’s Internet

Maxime Piraux, Tom Barbette, Nicolas Rybowski, Louis Navarre, Thomas Alfroy, Cristel Pelsser, François Michel, Olivier Bonaventure


The Internet use IP addresses to identify and locate network interfaces of connected devices. IPv4 was introduced more than 40 years ago and specifies 32-bit addresses. As the Internet grew, available IPv4 addresses eventually became exhausted more than ten years ago. The IETF designed IPv6 with a much larger addressing space consisting of 128-bit addresses, pushing back the exhaustion problem much further in the future.

In this paper, we argue that this large addressing space allows reconsidering how IP addresses are used and enables improving, simplifying and scaling the Internet. By revisiting the IPv6 addressing paradigm, we demonstrate that it opens up several research opportunities that can be investigated today. Hosts can benefit from several IPv6 addresses to improve their privacy, defeat network scanning, improve the use of several mobile access networks and their mobility as well as to increase the performance of multicore servers. Network operators can solve the multihoming problem more efficiently and without putting a burden on the BGP RIB, implement Function Chaining with Segment Routing, differentiate routing inside and outside a domain given particular network metrics and offer more fine-grained multicast services.

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The Packet Number Space Debate in Multipath QUIC

Quentin De Coninck


With a standardization process that attracted much interest, QUIC can be seen as the next general-purpose transport protocol. Still, it does not provide true multipath support yet, missing some use cases that Multipath TCP addresses. To fill that gap, the IETF recently adopted a Multipath proposal merging several proposed designs. While it focuses on its core components, there still remains one major design issue: the amount of packet number spaces that should be used. This paper provides experimental results with two different Multipath QUIC implementations based on NS3 simulations to understand the impact of using one packet number space per path or a single packet number space for the whole connection. Our results show that using one packet number space per path makes Multipath QUIC more resilient to the receiver’s heuristics to acknowledge packets and detect duplicates.

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Recommendations for Designing Hybrid Conferences

Vaibhav Bajpai, Oliver Hohlfeld, Jon Crowcroft, Srinivasan Keshav, Henning Schulzrine, Jorg Ott, Simone Ferlin-Reiter, Georg Carle, Andrew Hines, Alexander Raake


During the Covid-19 pandemic, many smaller conferences have moved entirely online and larger ones are being held as hybrid events. This reduces the carbon footprint of conference travel and
makes events more accessible to parts of the research community that have difficulty traveling long distances. Hybrid events will become an attractive alternative in the future since they make meetings broadly available without the need for travels, while preserving all elements of in-person gatherings. While we have developed a solid understanding of how to design virtual events, we do not yet know how to properly run hybrid events. We present guidelines and considerations–spanning technology, organization and social factors–for organizing successful hybrid conferences. This is the output of a Dagstuhl seminar on “Climate Friendly Internet Research” held in July 2021.

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A Case for an Open Customizable Cloud Network

Dean H. Lorenz, David Breitgand, Kathy Barabash, Etai Lev-Ran, Danny Raz


Cloud computing is transforming networking landscape over the last few years. The first order of business for major cloud providers today is to attract as many organizations as possible to their own clouds. To that end cloud providers offer a new generation of managed network solutions to connect the premises of the enterprises to their clouds. To serve their customers better and to innovate fast, major cloud providers are currently on the route to building their own “private Internets”, which are idiosyncratic. On the other hand, customers that do not want to stay locked by vendors and who want flexibility in using best-for-the-task services spanning multiple clouds and, possibly, their own premises, seek for solutions that will provide smart overlay connectivity across clouds.

The result of these developments is a multiplication of closed idiosyncratic solutions rather than an open standardized ecosystem. In this editorial note we argue for desirability of such an ecosystem, outline the main requirements and sketch possible solutions. We focus on enterprise as our primary use case and illustrate the main ideas through it, but the same principles apply to various different use cases.

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Measuring DNS over TCP in the Era of Increasing DNS Response Sizes: A View from the Edge

Mike Kosek, Trinh Viet Doan, Simon Huber, Vaibhav Bajpai


The Domain Name System (DNS) is one of the most crucial parts of the Internet. Although the original standard defined the usage of DNS over UDP (DoUDP) as well as DNS over TCP (DoTCP), UDP has become the predominant protocol used in the DNS. With the introduction of new Resource Records (RRs), the sizes of DNS responses have increased considerably. Since this can lead to truncation or IP fragmentation, the fallback to DoTCP as required by the standard ensures successful DNS responses by overcoming the size limitations of DoUDP. However, the effects of the usage of DoTCP by stub resolvers are not extensively studied to this date. We close this gap by presenting a view at DoTCP from the Edge, issuing 12.1M DNS requests from 2,500 probes toward Public as well as Probe DNS recursive resolvers. In our measurement study, we observe that DoTCP is generally slower than DoUDP, where the relative increase in Response Time is less than 37% for most resolvers. While optimizations to DoTCP can be leveraged to further reduce the response times, we show that support on Public resolvers is still missing, hence leaving room for optimizations in the future. Moreover, we also find that Public resolvers generally have comparable reliability for DoTCP and DoUDP. However, Probe resolvers show a significantly different behavior: DoTCP queries targeting Probe resolvers fail in 3 out of 4 cases, and, therefore, do not comply with the standard. This problem will only aggravate in the future: As DNS response sizes will continue to grow, the need for DoTCP will solidify.

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Programming Socket-Independent Network Functions with Nethuns

Nicola Bonelli, Fabio Del Vigna, Alessandra Fais, Giuseppe Lettieri, Gregorio Procissi


Software data planes running on commodity servers are very popular in real deployments. However, to attain top class performance, the software approach requires the adoption of accelerated network I/O frameworks, each of them characterized by its own programming model and API. As a result, network applications are often closely tied to the underlying technology, with obvious issues of portability over different systems. This is especially true in cloud scenarios where different I/O frameworks could be installed depending on the configuration of the physical servers in the infrastructure. The nethuns library proposes a unified programming abstraction to access and manage network operations over different I/O frameworks. The library is freely available to the community under the BSD license and currently supports AF_XDP and netmap for fast packet handling along with the classic AF_PACKET and the pcap library. Network applications based on nethuns need only to be re-compiled to run over a different network API. The experiments prove that the overhead introduced by nethuns is negligible, hence making it a convenient programming platform that eases the coding process while guaranteeing high performance and portability. As proofs of concept, a handy traffic generator as well as the popular Open vSwitch application have been successfully ported and tested over nethuns.

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Hyper-Specific Prefixes: Gotta Enjoy the Little Things in Interdomain Routing

Khwaja Zubair Sediqi, Lars Prehn, Oliver Gasser


Autonomous Systems (ASes) exchange reachability information between each other using BGP—the de-facto standard inter-AS routing protocol. While IPv4 (IPv6) routes more specific than /24 (/48) are commonly filtered (and hence not propagated), route collectors still observe many of them. In this work, we take a closer look at those hyper-specific prefixes (HSPs). In particular, we analyze their prevalence, use cases, and whether operators use them intentionally or accidentally. While their total number increases over time, most HSPs can only be seen by route collector peers. Nonetheless, some HSPs can be seen constantly throughout an entire year and propagate widely. We find that most HSPs represent (internal) routes to peering infrastructure or are related to address block relocations or blackholing. While hundreds of operators intentionally add HSPs to well-known routing databases, we observe that many HSPs are possibly accidentally leaked routes.

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One Bad Apple Can Spoil Your IPv6 Privacy

Said Jawad Saidi, Oliver Gasser, Georgios Smaragdakis


IPv6 is being more and more adopted, in part to facilitate the millions of smart devices that have already been installed at home. Unfortunately, we find that the privacy of a substantial fraction of end-users is still at risk, despite the efforts by ISPs and electronic vendors to improve end-user security, e.g., by adopting prefix rotation and IPv6 privacy extensions. By analyzing passive data from a large ISP, we find that around 19% of end-users’ privacy can be at risk. When we investigate the root causes, we notice that a single device at home that encodes its MAC address into the IPv6 address can be utilized as a tracking identifier for the entire end-user prefix—even if other devices use IPv6 privacy extensions. Our results show that IoT devices contribute the most to this privacy leakage and, to a lesser extent, personal computers and mobile devices. To our surprise, some of the most popular IoT manufacturers have not yet adopted privacy extensions that could otherwise mitigate this privacy risk. Finally, we show that third-party providers, e.g., hypergiants, can track up to 17% of subscriber lines in our study.

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