Since its introduction in 1987, the DNS has become one of the core components of the Internet. While it was designed to work with both TCP and UDP, DNS-over-UDP (DoUDP) has become the default option due to its low overhead. As new Resource Records were introduced, the sizes of DNS responses increased considerably. This expansion of the message body has led to truncation and IP fragmentation more often in recent years where large UDP responses make DNS an easy vector for amplifying denial-of-service attacks which can reduce the resiliency of DNS services. This paper investigates the resiliency, responsiveness, and usage of DoTCP and DoUDP over IPv4 and IPv6 for 10 widely used public DNS resolvers. The paper specifically measures the resiliency of the DNS infrastructure in the age of increasing DNS response sizes that lead to truncation and fragmentation. Our results offer key insights into the management of robust and reliable DNS network services. While DNS Flag Day 2020 recommends 1232 bytes of buffer sizes, we find out that 3/10 resolvers mainly announce very large EDNS(0) buffer sizes both from the edge as well as from the core, which potentially causes fragmentation. In reaction to large response sizes from authoritative name servers, we find that resolvers do not fall back to the usage of DoTCP in many cases, bearing the risk of fragmented responses. As the message sizes in the DNS are expected to grow further, this problem will become more urgent in the future. This paper demonstrates the key results (particularly as a consequence of the DNS Flag Day 2020) which may support network service providers make informed choices to better manage their critical DNS services.

DNS is crucial for the Internet, but vulnerable due to plaintext traffic. Despite efforts to standardize Domain Name System (DNS) encryption, its adoption remains limited. Users often lack awareness of privacy risks and the knowledge to enable encryption. To address this, the IETF standardized a new protocol; Discovery of Designated Resolvers (DDR), enabling automatic discovery and upgrade from unencrypted to encrypted DNS traffic. In this study, we present an empirical investigation of the DDR protocol, focusing on its adoption, configuration, and the operational challenges associated with enabling automated transitions to encrypted DNS communication via DNS over Encryption (DoE) protocols. Our results reveal widespread misconfigurations, including incomplete and incorrect DDR configurations that prevent clients from successfully transitioning to encrypted resolvers. In over 99 % of observed cases, DDR-compliant clients may fail to upgrade to DoE due to these deployment issues, underscoring the limitations of DDR in the wild. Additionally, we note a severe resolver consolidation induced by current DDR deployments, as >97 % of DDR-enabled resolvers delegate to major DNS cloud providers, raising concerns about privacy and governance.

Every Web session involves a DNS resolution. While, in the last decade, we witnessed a promising trend towards an encrypted Web in general, DNS encryption has only recently gained traction with the standardisation of DNS over TLS (DoT) and DNS over HTTPS (DoH). Meanwhile, the rapid rise of QUIC deployment has now opened up an exciting opportunity to utilise the same protocol to not only encrypt Web communications, but also DNS. In this paper, we evaluate this benefit of using QUIC to coalesce name resolution via DNS over QUIC (DoQ), and Web content delivery via HTTP/3 (H3) with 0-RTT. We compare this scenario using several possible combinations where H3 is used in conjunction with DoH and DoQ, as well as the unencrypted DNS over UDP (DoUDP). We observe, that when using H3 1-RTT, page load times with DoH can get inflated by >30% over fixed-line and by >50% over mobile when compared to unencrypted DNS with DoUDP. However, this cost of encryption can be drastically reduced when encrypted connections are coalesced (DoQ + H3 0-RTT), thereby reducing the page load times by 1/3 over fixed-line and 1/2 over mobile, overall making connection coalescing with QUIC the best option for encrypted communication on the Internet.

Emerging Remote Piloting (RP) operations of electrified Unmanned Aerial Vehicles (UAVs) demand low-latency and high-quality video delivery to conduct safe operations in the low-altitude airspace. Although cellular networks are one of the prominent candidates to provide connectivity for such operations, their ground-centric nature limits their capabilities in achieving seamless and reliable aerial connectivity. In this paper, we study the feasibility of supporting RP operations with low latency and high-quality video delivery over commercial cellular networks. By setting up an adaptive bitrate video transmission pipeline with the Google Congestion Control (GCC) and Self-Clocked Rate Adaptation for Multimedia (SCReAM) Congestion Control (CC) algorithms, we analyze the video delivery performance for the RP application requirements and compare the performance of GCC and SCReAM against constant bitrate video delivery. Our results show that low-latency video delivery with < 300 ms playback latency between full-HD and 4K resolution can be maintained up to about 95% of the time in the air. While static bitrate video delivery outperforms adaptive streaming in urban location with abundant link capacity, the latter becomes advantageous in rural locations, where the link capacity is affected by fluctuations. Although the study's findings highlight the capabilities of cellular networks in delivering low-latency video for a safety-critical aerial service, we also discuss the potential improvements and future research challenges for enabling safe operations and meeting the service requirements using cellular networks. We release our collected traces and the video transmission pipeline as open-source to facilitate research in this field.

Over the last decade, Web traffic has significantly shifted towards HTTPS due to an increased awareness for privacy. However, DNS traffic is still largely unencrypted, which allows user profiles to be derived from plaintext DNS queries. While DNS over TLS (DoT) and DNS over HTTPS (DoH) address this problem by leveraging transport encryption for DNS, both protocols are constrained by the underlying transport (TCP) and encryption (TLS) protocols, requiring multiple round-trips to establish a secure connection. In contrast, QUIC combines the transport and cryptographic handshake into a single round-trip, which allows the recently standardized DNS over QUIC (DoQ) to provide DNS privacy with minimal latency. In the first study of its kind, we perform distributed DoQ measurements across multiple vantage points to evaluate the impact of DoQ on Web performance. We find that DoQ excels over DoH, leading to significant improvements with up to 10% faster loads for simple webpages. With increasing complexity of webpages, DoQ even catches up to DNS over UDP (DoUDP) as the cost of encryption amortizes: With DoQ being only ~2% slower than DoUDP, encrypted DNS becomes much more appealing for the Web.

With the pioneering introduction of autonomous vehicles, system failures while driving from A to B are more likely to occur. In such scenarios one option is to hand back the control to the human driver, if someone suitable is inside the vehicle. Teleoperated Driving, the remote control of vehicles by human operators, can be a solution to scenarios without suitable drivers inside. A video stream is used to provide operators with an overview of the vehicle’s environment and support for a safe remote control. By utilizing cellular networks as wireless communication medium for Teleoperated Driving, the available bandwidth is a limiting factor. This paper introduces a multi-step approach to lower the bandwidth requirements, which is achieved by initially splitting the single video stream into two parts: One part conveying the original video information restricted to important objects and the remainder, to which various filters are applied. Results show that this approach can lead to a decreased bandwidth consumption. These results are validated with a user study, where participants had to rate the perceived video quality and the driveability for the different combinations. This user study shows that, for every investigated scenario, at least one combination of parameters (applied filters) was rated driveable. Finally, the results are used to sketch a system that infers specific combinations of parameters based on the environmental conditions and the available bitrate.

“Roam like Home” is the initiative of the European Commission (EC) to end the levy of extra charges when roaming within the European region. As a result, people can use data services more freely across Europe. However, the implications of roaming solutions on network performance have not been carefully examined yet. This paper provides an in-depth characterization of the implications of international data roaming within Europe. We build a unique roaming measurement platform using 16 different mobile networks deployed in six countries across Europe. Using this platform, we measure different aspects of international roaming in 4G networks in Europe, including mobile network configuration, performance characteristics, and quality of experience. We find that operators adopt a common approach to implement roaming called Home-routed roaming (HR). This results in additional latency penalties of 60 ms or more, depending on geographical distance. This leads to worse browsing performance, with an increase in the metrics related to Quality of Experience (QoE) of users (Page Load time and Speed Index) in the order of 15-20 percent. We further analyze in isolation the impact of latency on QoE metrics and find that the penalty imposed by HR leads to a degradation on QoE metrics up to 150 percent in case of intercontinental roaming.

QUIC was launched in 2013 with a goal to provide reliable, connection-oriented and end-to-end encrypted transport and is recently standardized in May 2021 by the Internet Engineering Task Force (IETF). This work evaluates QUIC performance over the web, cloud storage, and video workloads and compares them to traditional TLS/TCP. To this end, we have designed tests (quic_perf,tls_perfandvideo) and conducted measurements from 2018 – 2021 using multiple vantage points: an educational network, a high-bandwidth low-RTT residential link in Germany and a low-bandwidth high-RTT residential link in India. We target Alexa Top-1M for web workloads and probe them towards the support for QUIC, TLS 1.2 and TLS 1.3. By measuring$\lt 5.7$K websites that support QUIC, we observe that QUIC has up to$\approx 140$% lower mean connection times than TLS 1.2/1.3 over TCP for low-bandwidth and high-RTT networks. When comparing different versions of QUIC, we observe that IETF QUIC connection times are slightly better than different versions (Q050,Q046,Q044,Q043,Q039andQ035) of gQUIC. For cloud storage workloads, we observe that TLS 1.2 over TCP exhibits higher throughput for larger file sizes (>20 MB up to 2 GB), while QUIC exhibits higher throughput for smaller file sizes ($\leq 20$MB) while downloading files from Google Drive. At the same time, QUIC has much higher CPU utilization than TLS 1.2 over TCP, almost double while downloading a large file (200 MB) from Google Drive due to in-kernel optimizations that benefit TCP. For video workloads, we observe that QUIC is 534 ms faster than TLS 1.2 over TCP from India (406 ms from Germany) in establishing a connection to YouTube media servers. Although we witness that (similar to cloud storage workloads) the overall download rate is higher over TLS, QUIC still tends to depict better video content delivery with reduced stall events and up to 50% lower stall durations due to its lower latency overheads. To support reproducibility, the developed tests and the collected data are made publicly available to the community.

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.

Network support for Unmanned Aerial Vehicles (UAVs) is raising an interest among researchers due to the strong potential applications. However, current knowledge on UAV data traffic is mainly based on conceptual studies and does not provide an in-depth insight on the data traffic properties. To close this gap, we present a measurement-based study analyzing in detail the Control and Non-payload Communication (CNPC) traffic produced by three different UAVs when communicating with their remote controller over 802.11 protocol. We analyze the traffic in terms of data rate, inter-packet interval and packet length distributions, and identify their main influencing factors. The data traffic appears neither deterministic nor periodic but bursty, with a tendency towards Poisson traffic. We further create an understanding on how the traffic of the investigated UAVs are internally generated and propose a model to analytically capture their traffic processes, which provides an explanation for the observed behavior. We implemented a publicly available UAV traffic generator "AVIATOR" based on the proposed traffic model and verified the model by comparing the simulated traces with the experimental results.

Recent studies have shown centralization in the Domain Name System (DNS) around public DNS services, which are hosted on centrally managed infrastructure and advertise higher reliability, improved security, and faster response times for name resolutions. However, many of the recently emerged public DNS services have not yet been extensively studied regarding popularity and performance. In light of this, we use 10.6k RIPE Atlas probes and find that 28.3% of the probes (and the their host network by extension) use at least one public DNS service, with Google being the most popular public DNS service among these probes. We further quantify the response time benefits of such public DNS services using ≈2.5k RIPE Atlas probes deployed in home networks (1k of which are IPv6 capable): Overall, we provision around 12.7M DNS requests based on a set of 23 domains and ten centralized public DNS services both over IPv4 and IPv6. For comparison, we additionally resolve the same set of domains using the probes' local resolvers, which are typically managed by the ISP and exhibit lower response times in general. We observe that even though IP and AS paths to local resolvers are generally shorter, some public DNS services (e.g., Cloudflare), achieve faster responses over both IPv4 and IPv6. Across all continents, Cloudflare, Google, and OpenDNS exhibit the lowest response times out of all public resolvers for successful DNS measurements. Probes in Europe (EU) and North America (NA) experience comparable latencies to public and local resolvers, thereby diminishing claimed latency benefits of public resolvers. We also observe inflated path lengths to and response times (over both address families) from most public resolvers for probes in Africa (AF) and South America (SA). Based on our observations, we provide recommendations and discuss situations in which switching to public DNS services may be beneficial.

The increasing trend of the traffic demand from mobile users and the presence of limited resources creates a challenge for network resource management. Understanding the data usage pattern and traffic demand of mobile users is a way forward to enable data-driven network resource management. However, due to the complex nature of mobile networks, understanding and characterizing data usage pattern of mobile users is a daunting task. In this work, we investigate and characterize data usage patterns and behavior of users in mobile networks. We leverage a dataset (~340 M records) collected through a crowd-based mobile network measurement platform - Netradar - across six countries. We elucidate different network factors and study how they affect the data usage patterns by taking mobile users in Finland as a use case. We perform a comparison on data usage patterns of mobile users across six countries by considering total data consumption, network access, the number of sessions created per user, throughput, and user satisfaction level on services. We show that data usage behavior of users over a mobile network is primarily driven by user mobility, the type of data subscription plan marketed by Mobile Network Operators (MNOs), network congestion, and network coverage. Besides, the data usage patterns over different network technologies (e.g., preferring cellular over WiFi) and the percentage of users accessing congested networks vary by country; mostly due to the market pricing strategy and radio coverage. However, the overall data consumption (cellular and WiFi) is comparatively similar in most of the countries we studied.

We present an active measurement test (netflix) that downloads content from the Netflix content delivery network. The test measures latency and achievable throughput as key performance indicators when downloading the content from Netflix. We deployed the test on ~100 SamKnows probes connected to dual-stacked networks representing 74 different origin ASes. Using a ~2.75 year-long (Jul 2016-Apr 2019) dataset, we observe Netflix Open Connect Appliance (OCA) infrastructure to be highly available, although some vantage points experience low success rates connecting over IPv6. We witness that clients prefer connecting to Netflix OCAs over IPv6, although the preference over IPv6 tends to drop over certain peak hours during the day. The TCP connect times toward the OCAs have reduced by ~40% and the achievable throughput has increased by 20% over the measurement duration. We also provision scamper right after the netflix test to capture the forwarding path toward the Netflix OCAs. We observe that the Netflix OCA caches deployed inside the ISP are reachable within six IP hops and can reduce IP path lengths by 40% over IPv4 and by half over IPv6. Consequently, TCP connect times are reduced by 64% over both address families. The achieved throughput can~ also increase by a factor of three when such ISP caches are used to stream content. This is the first study to measure Netflix content delivery from residential networks, since the inception of the Netflix CDN infrastructure in 2011. To encourage reproducibility of our work, an anonymized version of the entire longitudinal dataset is publicly released.

This paper presents Webget, a measurement tool that measures Web quality of service (QoS) metrics, including the DNS lookup time, time to first byte (TTFB), and the download time. Webget also captures Web complexity metrics, such as the number and the size of objects that make up the website. We deploy the Webget test to measure the Web performance of Google, YouTube, and Facebook from 182 SamKnows probes. Using a 3.5-year-long (January 2014-July 2017) dataset, we show that the DNS lookup time of these popular content delivery networks (CDNs) and the download time of Google have improved over time. We also show that the TTFB toward Facebook exhibits worse performance than the Google CDN. Moreover, we show that the number and the size of objects are not the only factors that affect the Web download time. We observe that these webpages perform differently across regions and service providers. We also developed a Web measurement system, Web performance and rendering (WePR) that measures the same Web QoS and complexity metrics as Webget, but it also captures the Web quality of experience metrics, such as rendering time. WePR has a distributed architecture where the component that measures the Web QoS and complexity metrics is deployed on the SamKnows probe, while the rendering time is calculated on a central server. We measured the rendering performance of four websites. We show that in 80% of the cases, the rendering time of the websites is faster than the downloading time. The source code of the WePR system and the dataset is made publicly available.

IPv6 measurement studies have focussed on measuring IPv6 adoption, while studies on measuring IPv6 performance have either become dated or only provide a snapshot view. We provide a longitudinal view of the performance of dual-stacked websites. We show that (since 2013) latency towards ALEXA 10K websites with AAAA entries over the six years have reduced by 29% over IPv4 and by 57% over IPv6. As of Dec 2018, 56% of these websites are faster over IPv6 with 95% of the rest being at most 1 ms slower. We also identify glitches in web content delivery that once fixed can help improve the user experience over IPv6. Using a publicly available dataset, we show that 40% of ALEXA 1M websites with AAAA entries were not accessible over IPv6 in 2009. These complete failures have reduced to 1.9% as of Jan 2019. However, our data collection on partial failures helps identify further that 27% of these popular websites with AAAA entries still suffer from partial failure over IPv6. These partial failures are affected by DNS resolution errors on images, javascript and CSS content. For 12% of these websites, more than half of the content belonging to same-origin sources fails over IPv6, while analytics and third-party advertisements contribute to failures from cross-origin sources. Our results also contribute to the IETF standardisation process. We witness that using an happy eyeballs timer value of 250 ms, clients prefer IPv6 connections to 99% of ALEXA 10 K websites (with AAAA entries) more than 96% of the time. Although, this makes clients prefer slower IPv6 connections in 81% of the cases. Our results show that a Happy Eyeballs (MBA) timer value of 150 ms does not severly affect IPv6 preference towards websites. The entire dataset presenting results on partial failures, latency and HE used in this paper is publicly released.

"Roam like Home" is the initiative of the European Commission (EC) to end the levy of extra charges when roaming within the European region. As a result, people are able to use data services more freely across Europe. However, the implications roaming solutions have on performance have not been carefully examined. This paper provides an in-depth characterization of the implications of international data roaming within Europe. We build a unique roaming measurement platform using 16 different mobile networks deployed in six countries across Europe. Using this platform, we measure different aspects of international roaming in 3G and 4G networks, including mobile network configuration, performance characteristics, and content discrimination. We find that operators adopt common approaches to implementing roaming, resulting in additional latency penalties of ∼60 ms or more, depending on geographical distance. Considering content accessibility, roaming poses additional constraints that leads to only minimal deviations when accessing content in the original country. However, geographical restrictions in the visited country make the picture more complicated and less intuitive.

No abstract available.

The throughput of a cellular network depends on a number of factors such as radio technology, limitations of device hardware (e.g., chipsets, antennae), physical layer effects (interference, fading, etc.), node density and demand, user mobility, and the infrastructure of Mobile Network Operators (MNO). Therefore, understanding and identifying the key factors of cellular network performance that affect end-users experience is a challenging task. We use a dataset collected using netradar, a platform that measures cellular network performance crowd- sourced from mobile user devices. Using this dataset we develop a methodology (a classifier using a machine learning approach) for understanding cellular network performance. We examine key characteristics of cellular networks related to throughput from the perspective of mobile user activity, MNO, smartphone models, link stability, location and time of day. We perform a network-wide correlation and statistical analysis to obtain a basic understanding of the influence of individual factors. We use a machine learning approach to identify the important features and to understand the relationship between different ones. These features are then used to build a model to classify the stability of cellular network based on the data reception characteristics of the user. We show that it is possible to classify reasons for network instability using minimal cellular network metrics with up to 90% of accuracy.

There is significant interest in the technical and policy communities regarding the extent, scope, and consumer harm of persistent interdomain congestion. We provide empirical grounding for discussions of interdomain congestion by developing a system and method to measure congestion on thousands of interdomain links without direct access to them. We implement a system based on the Time Series Latency Probes (TSLP) technique that identifies links with evidence of recurring congestion suggestive of an under-provisioned link. We deploy our system at 86 vantage points worldwide and show that congestion inferred using our lightweight TSLP method correlates with other metrics of interconnection performance impairment. We use our method to study interdomain links of eight large U.S. broadband access providers from March 2016 to December 2017, and validate our inferences against ground-truth traffic statistics from two of the providers. For the period of time over which we gathered measurements, we did not find evidence of widespread endemic congestion on interdomain links between access ISPs and directly connected transit and content providers, although some such links exhibited recurring congestion patterns. We describe limitations, open challenges, and a path toward the use of this method for large-scale third-party monitoring of the Internet interconnection ecosystem.

RIPE Atlas consists of ∼9.1K probes (as of Jan 2017) connected in core, access and home networks. RIPE Atlas has recently (Jul 2014) introduced a tagging mechanism for fine-grained vantage point selection of probes. These tags are subdivided into user and system tags. User tags are based on a manual process which is largely dependent on proactive participation of probe hosts. We show that only ∼2.8% of probe hosts ever update their user tags which may lead to user tags that tend to become stale over time. System tags on the other hand being automatically assigned and frequently updated (every 4 hours) are stable and accurate. We show an application of system tags by performing a vantage point selection of dual-stacked probes. This exploration reveals that with ∼2.3K (∼26%) connected dual-stacked probes, RIPE Atlas provides the richest source of vantage points for IPv6 measurement studies. These dual-stacked probes span 88 countries and cover 822 ASNs. ∼83% of these dual-stacked probes are connected within access networks with 782 probes deployed at homes with native IPv6 connectivity. These home dual-stacked probes are evenly split across DSL, cable and fibre deployments. We show that IPv6 latencies from these probes to RIPE Atlas anchors appear comparable to IPv4, although IPv4 performs marginally better. By applying a correlation against APNIC IPv6 user population estimate, we further reveal underrepresented countries (such as BE and JP) which would benefit from deployment of more probes for IPv6 measurement studies.

A number of large-scale network measurement platforms have emerged in the last few years. These platforms have deployed thousands of measurement probes at strategic locations within the access and backbone networks and at residential gateways. The primary goal of these efforts is typically to measure the performance of broadband access networks and to help regulators sketch better policy decisions. In this dissertation we expand the goal further by using large-scale measurement platforms to understand the impact of network infrastructure changes. We deploy probes at the edge of the network to measure IPv6 performance and to dissect last-mile latency characteristics of access networks.

Cisco's NetFlow protocol and Internet engineering task force's Internet protocol flow information export open standard are widely deployed protocols for collecting network flow statistics. Understanding intricate traffic patterns in these network statistics requires sophisticated flow analysis tools that can efficiently mine network flow records. We present a network flow query language (NFQL), which can be used to write expressive queries to process flow records, aggregate them into groups, apply absolute or relative filters, and invoke Allen interval algebra rules to merge group records. We demonstrate nfql, an implementation of the language that has comparable execution times to SiLK and flow-tools with absolute filters. However, it trades performance when grouping and merging flows in favor of more operational capabilities that help increase the expressiveness of NFQL. We present two applications to demonstrate richer capabilities of the language. We show queries to identify flow signatures of popular applications and behavioural signatures to identify SSH compromise detection attacks.

We compare the similarity of webpages delivered over IPv4 and IPv6. Using the SamKnows web performance (webget) test, we implemented an extension (simweb) that allows us to measure the similarity of webpages. The simweb test measures against ALEXA top 100 dual-stacked websites from 80 SamKnows probes connected to dual-stacked networks representing 58 different ASes. Using a two months-long dataset we show that 14% of these dual-stacked websites exhibit a dissimilarity in the number of fetched webpage elements, with 94% of them exhibiting a dissimilarity in their size. We show that 6% of these websites announce AAAA entries in the DNS but no content is delivered over IPv6 when an HTTP request is made. We also noticed several cases where not all webpage elements (such as images, javascript and CSS) of a dual-stacked website are available over IPv6. We show that 27% of the dual-stacked websites have some fraction of webpage elements that fail over IPv6, with 9% of the websites having more than 50% webpage elements that fail over IPv6. We perform a causality analysis and also identify sources for these failing elements. We show that 12% of these websites have more than 50% webpage elements that belong to the same origin source and fail over IPv6. Failure rates are largely affected by DNS resolution error on images, javascript and CSS content delivered from both same-origin and cross-origin sources. These failures tend to cripple experience for users behind an IPv6-only network and a quantification of failure cases may help improve IPv6 adoption on the Internet.

We compare IPv4 and IPv6 connectivity of dual-stacked hosts using a metric that measures Transmission Control Protocol (TCP) connection establishment time to 100 popular dual-stacked websites. We have deployed an implementation of this metric on 20 SamKnows probes connected to dual-stacked networks that are part of 18 different Autonomous Systems (AS). Using a year-long dataset gathered from these vantage points, we show how most of these websites centralise around Content Delivery Network (CDN) deployments and consequently show similar performance. We show that these CDN clusters are different for IPv4 and IPv6. Furthermore, some of these websites tend to be served by CDN caches deployed within service provider networks. We show how these CDN caches are largely absent over IPv6. The distributions of TCP connect times show how clusters serving popular websites over IPv6 have improved over time. We also illustrate cases where network policies inhibit hosts from connecting to websites over IPv6.

Network Configuration (NETCONF) is being considered by the Internet Engineering Task Force (IETF) as one of the control protocol candidates within the Large-Scale Measurement of Broadband Performance (LMAP) framework. We demonstrate the possibility of managing LMAP Measurement Agent (MA)s using the NETCONF protocol. We have deployed a NETCONF server on one such MA: a SamKnows measurement probe. The server is built around the libnetconf library, and has been heavily optimized to accommodate it to the limitations of the SamKnows hardware.

Interoperability testing is an important part of the lifecycle of a protocol. Interoperability tests not only help to reduce implementation bugs, but they also often improve the accuracy of a protocol specification. In a pursuit to improve Network Configuration (NETCONF) interoperability and foster it for community-based education, we have developed and deployed a NETCONF Interoperability Lab. The lab provides a platform to execute test-cases against an online catalogue of NETCONF server and client implementations. The NETCONF Interoperability lab is available online at: http://www.interop-lab.net.

The Internet Engineering Task Force (IETF) has developed protocols that promote a healthy IPv4 and IPv6 co-existence. The happy eyeballs algorithm for instance, provides recommendations to application developers to help prevent bad user experience in situations where IPv6 connectivity is broken. In this paper, we compare the IPv4 and IPv6 connectivity of a dual-stacked host using a metric that measures the Transmission Control Protocol (TCP) connection establishment time to a number of popular web services. We witnessed several cases where the connection establishment times and their variations over IPv6 are higher.