Andra Lutu

Measuring and assessing mobile broadband networks with MONROE

Mobile broadband (MBB) networks underpin numerous vital operations of the society and are arguably becoming the most important piece of the communications infrastructure. In this demo paper, our goal is to showcase the potential of a novel multi-homed MBB platform for measuring, monitoring and assessing the performance of MBB services in an objective manner. Our platform, MONROE, is composed of hundreds of nodes scattered over four European countries and a backend system that collects the measurement results. Through a user-friendly web client, the experimenters can schedule and deploy their experiments. The platform further embeds traffic analysis tools for real-time traffic flow analysis and a powerful visualization tool.

Experience: An Open Platform for Experimentation with Commercial Mobile Broadband Networks

Open experimentation with operational Mobile Broadband (MBB) networks in the wild is currently a fundamental requirement of the research community in its endeavor to address the need of innovative solutions for mobile communications. Even more, there is a strong need for objective data about stability and performance of MBB (e.g., 3G/4G) networks, and for tools that rigorously and scientifically assess their status. In this paper, we introduce the MONROE measurement platform: an open access and flexible hardware-based platform for measurements and custom experimentation on operational MBB networks. The MONROE platform enables accurate, realistic and meaningful assessment of the performance and reliability of 11 MBB networks in Europe. We report on our experience designing, implementing and testing the solution we propose for the platform. We detail the challenges we overcame while building and testing the MONROE testbed and argue our design and implementation choices accordingly. We describe and exemplify the capabilities of the platform and the wide variety of experiments that external users already perform using the system.

Separating wheat from chaff: Winnowing unintended prefixes using machine learning

In this paper, we propose the use of prefix visibility at the interdomain level as an early symptom of anomalous events in the Internet. We focus on detecting anomalies which, despite their significant impact on the routing system, remain concealed from state of the art tools. We design a machine learning system to winnow the prefixes with unintended limited visibility - symptomatic of anomalous events - from the prefixes with intended limited visibility - resulting from legitimate routing operations. We train a winnowing algorithm with ground-truth data on 20,000 operational limited visibility prefixes (LVPs) already classified by the operators of the origin networks. The ground-truth was collected using the BGP Visibility Scanner, a tool we developed to provide operators with a multi-angle view on the efficacy of their routing policies. We build a dataset with the pre-classified prefixes and the features describing their visibility status dynamics. We further use this dataset to derive a boosted decision tree which winnows unintended LVPs with an accuracy of 95%.

Understanding the Reachability of IPv6 Limited Visibility Prefixes

The main functionality of the Internet is to provide global connectivity for every node attached to it. In light of the IPv4 address space depletion, large networks are in the process of deploying IPv6. In this paper we perform an extensive analysis of how BGP route propagation affects global reachability of the active IPv6 address space in the context of this unique transition of the Internet infrastructure. We propose and validate a methodology for testing the reachability of an IPv6 address block active in the routing system. Leveraging the global visibility status of the IPv6 prefixes evaluated with the BGP Visibility Scanner, we then use this methodology to verify if the visibility status of the prefix impacts its reachability at the interdomain level. We perform active measurements using the RIPE Atlas platform. We test destinations with different BGP visibility degrees (i.e., limited visibility - LV, high visibility - HV and dark prefixes). We show that the IPv6 LV prefixes (v6LVPs) are generally reachable, mostly due to a less-specific HV covering prefix (v6HVP). However, this is not the case of the dark address space, which, by not having a covering v6HVP is largely unreachable.

NAT Revelio: Detecting NAT444 in the ISP

In this paper, we propose NAT Revelio, a novel test suite and methodology for detecting NAT deployments beyond the home gateway, also known as NAT444 (e.g., Carrier Grade NAT). Since NAT444 solutions may impair performance for some users, understanding the extent of NAT444 deployment in the Internet is of interest to policymakers, ISPs, and users. We perform an initial validation of the NAT Revelio test suite within a controlled NAT444 trial environment involving operational residential lines managed by a large operator in the UK. We leverage access to a unique SamKnows deployment in the UK and collect information about the existence of NAT444 solutions from 2,000 homes and 26 ISPs. To demonstrate the flexibility of NAT Revelio, we also deployed it in project BISmark, an open platform for home broadband internet research. We analyze the results and discuss our findings.

An economic side-effect for prefix deaggregation

The injection of artificially fragmented prefixes through BGP is a widely used traffic engineering technique. In this paper we examine one particular economic side-effect of deaggregation, namely the impact on the transit traffic bill. We show that the use of more-specific prefixes has a traffic stabilization side-effect which translates into a decrease of the transit traffic bill. We propose an analytical model in order to quantify the impact of deaggregation on the transit costs. We validate our results by means of simulations and through the extensive analysis of real BGP routing information data.

Path transparency measurements from the mobile edge with PATHspider

Network operators and equipment vendors can hesitate to deploy network protocol innovations in fear of breaking connectivity for end users. To assess the potential for evolution of the protocol stack, it is important to know the existing network impairments and opportunities to work around the impairments. While classical network measurement tools often focus on absolute performance values, PATHspider is an extensible framework for performing and analyzing A/B testing between two different protocols or different protocol extensions. It thus enables controlled experiments in search of protocol-dependent connectivity problems, and to identify differential treatment. This paper presents how PATHspider can be instrumented to assess path transparency over commercial mobile networks, using the MONROE platform. We provide here proof-of-concept results from measurements in a UK commercial mobile network, and lay out our future measurement plans for PATHspider using the MONROE testbed in Europe.

The BGP visibility toolkit: detecting anomalous internet routing behavior

In this paper, we propose the BGP Visibility Toolkit, a system for detecting and analyzing anomalous behavior in the Internet. We show that interdomain prefix visibility can be used to single out cases of erroneous demeanors resulting from misconfiguration or bogus routing policies. The implementation of routing policies with BGP is a complicated process, involving fine-tuning operations and interactions with the policies of the other active ASes. Network operators might end up with faulty configurations or unintended routing policies that prevent the success of their strategies and impact their revenues. As part of the Visibility Toolkit, we propose the BGP Visibility Scanner, a tool which identifies limited visibility prefixes in the Internet. The tool enables operators to provide feedback on the expected visibility status of prefixes. We build a unique set of ground-truth prefixes qualified by their ASes as intended or unintended to have limited visibility. Using a machine learning algorithm, we train on this unique dataset an alarm system that separates with 95% accuracy the prefixes with unintended limited visibility. Hence, we find that visibility features are generally powerful to detect prefixes which are suffering from inadvertent effects of routing policies. Limited visibility could render a whole prefix globally unreachable. This points towards a serious problem, as limited reachability of a non-negligible set of prefixes undermines the global connectivity of the Internet. We thus verify the correlation between global visibility and global connectivity of prefixes.

The good, the bad and the implications of profiling mobile broadband coverage

Pervasive coverage and continuous connectivity of Mobile Broadband (MBB) networks are common goals for regulators and operators. Given the increasing heterogeneity of technologies in the last mile of MBB networks, further support for seamless connectivity across multiple network types relies on understanding the prevalent network coverage profiles that capture different available technologies in an area. Correlating these coverage profiles with network performance metrics is of great importance in order to forestall disturbances for applications running on top of MBB networks. In this paper, we aim to profile MBB coverage and its performance implications from the end-users perspective along critical transport infrastructures (i.e., railways in Norway). For this, we deploy custom measurement nodes on-board five Norwegian inter-city trains and we collect a unique geo-tagged dataset along the train routes. We then build a coverage mosaic, where we divide the routes into segments and analyze the coverage of individual operators in each segment. We propose and evaluate the use of hierarchical clustering to describe prevalent coverage profiles of MBB networks along the train routes and classify each segment accordingly. We further analyze the areas we classify with each profile and assess the packet-loss and HTTP download performance of the networks in those areas.

Informing Protocol Design Through Crowdsourcing: the Case of Pervasive Encryption

Middleboxes, such as proxies, firewalls and NATs play an important role in the modern Internet ecosystem. On one hand, they perform advanced functions, e.g. traffic shaping, security or enhancing application performance. On the other hand, they turn the Internet into a hostile ecosystem for innovation, as they limit the deviation from deployed protocols. It is therefore essential, when designing a new protocol, to first understand its interaction with the elements of the path. The emerging area of crowdsourcing solutions can help to shed light on this issue. Such approach allows us to reach large and different sets of users and also different types of devices and networks to perform Internet measurements. In this paper, we show how to make informed protocol design choices by using a crowdsourcing platform. We consider a specific use case, namely the case of pervasive encryption in the modern Internet. Given the latest public disclosures of the NSA global surveillance operations, the issue of privacy in the Internet became of paramount importance. Internet community efforts are thus underway to increase the adoption of encryption. Using a crowdsourcing approach, we perform large-scale TLS measurements to advance our understanding on whether wide adoption of encryption is possible in todays Internet.