Leveraging Conventional Internet Routing Protocol Behavior to Defeat DDoS and Adverse Networking Conditions

The Internet is a cornerstone of modern society. Yet increasingly devastating attacks against the Internet threaten to undermine the Internet\u27s success at connecting the unconnected. Of all the adversarial campaigns waged against the Internet and the organizations that rely on it, distributed denial of service, or DDoS, tops the list of the most volatile attacks. In recent years, DDoS attacks have been responsible for large swaths of the Internet blacking out, while other attacks have completely overwhelmed key Internet services and websites. Core to the Internet\u27s functionality is the way in which traffic on the Internet gets from one destination to another. The set of rules, or protocol, that defines the way traffic travels the Internet is known as the Border Gateway Protocol, or BGP, the de facto routing protocol on the Internet. Advanced adversaries often target the most used portions of the Internet by flooding the routes benign traffic takes with malicious traffic designed to cause widespread traffic loss to targeted end users and regions. This dissertation focuses on examining the following thesis statement. Rather than seek to redefine the way the Internet works to combat advanced DDoS attacks, we can leverage conventional Internet routing behavior to mitigate modern distributed denial of service attacks. The research in this work breaks down into a single arc with three independent, but connected thrusts, which demonstrate that the aforementioned thesis is possible, practical, and useful. The first thrust demonstrates that this thesis is possible by building and evaluating Nyx, a system that can protect Internet networks from DDoS using BGP, without an Internet redesign and without cooperation from other networks. This work reveals that Nyx is effective in simulation for protecting Internet networks and end users from the impact of devastating DDoS. The second thrust examines the real-world practicality of Nyx, as well as other systems which rely on real-world BGP behavior. Through a comprehensive set of real-world Internet routing experiments, this second thrust confirms that Nyx works effectively in practice beyond simulation as well as revealing novel insights about the effectiveness of other Internet security defensive and offensive systems. We then follow these experiments by re-evaluating Nyx under the real-world routing constraints we discovered. The third thrust explores the usefulness of Nyx for mitigating DDoS against a crucial industry sector, power generation, by exposing the latent vulnerability of the U.S. power grid to DDoS and how a system such as Nyx can protect electric power utilities. This final thrust finds that the current set of exposed U.S. power facilities are widely vulnerable to DDoS that could induce blackouts, and that Nyx can be leveraged to reduce the impact of these targeted DDoS attacks

Multipath inter-domain policy routing

Dissertação submetida para a obtenção do grau de Doutor em Engenharia Electrotécnica e de ComputadoresRouting can be abstracted to be a path nding problem in a graph that models the network. The problem can be modelled using an algebraic approach that describes the way routes are calculated and ranked. The shortest path problem is the most common form and consists in nding the path with the smallest cost. The inter-domain scenario introduces some new challenges to the routing problem: the routing is performed between independently con gured and managed networks; the ranking of the paths is not based on measurable metrics but on policies; and the forwarding is destination based hop-by-hop. In this thesis we departed from the Border gateway Protocol (BGP) identifying its main problems and elaborating on some ideal characteristics for a routing protocol suited for the inter-domain reality. The main areas and contributions of this work are the following: The current state of the art in algebraic modeling of routing problems is used to provide a list of possible alternative conditions for the correct operation of such protocols. For each condition the consequences in terms of optimality and network restrictions are presented. A routing architecture for the inter-domain scenario is presented. It is proven that it achieves a multipath routing solution in nite time without causing forwarding loops. We discuss its advantages and weaknesses. A tra c-engineering scheme is designed to take advantage of the proposed architecture. It works using only local information and cooperation of remote ASes to minimize congestion in the network with minimal signalling. Finally a general model of a routing protocol based on hierarchical policies is used to study how e cient is the protocol operation when the correctness conditions are met. This results in some conclusions on how the policies should be chosen and applied in order to achieve speci c goals.Portuguese Science and Technology Foundation -(FCT/MCTES)grant SFRH/BD/44476/2008; CTS multi-annual funding project PEst OE/EEI/UI0066/2011; MPSat project PTDC/EEA TEL/099074/2008; OPPORTUNISTICCR project PTDC/EEA-TEL/115981/2009; Fentocells project PTDC/EEA TEL/120666/201

Abstracting network policies

Almost every human activity in recent years relies either directly or indirectly on the smooth and efficient operation of the Internet. The Internet is an interconnection of multiple autonomous networks that work based on agreed upon policies between various institutions across the world. The network policies guiding an institution’s computer infrastructure both internally (such as firewall relationships) and externally (such as routing relationships) are developed by a diverse group of lawyers, accountants, network administrators, managers amongst others. Network policies developed by this group of individuals are usually done on a white-board in a graph-like format. It is however the responsibility of network administrators to translate and configure the various network policies that have been agreed upon. The configuration of these network policies are generally done on physical devices such as routers, domain name servers, firewalls and other middle boxes. The manual configuration process of such network policies is known to be tedious, time consuming and prone to human error which can lead to various network anomalies in the configuration commands. In recent years, many research projects and corporate organisations have to some level abstracted the network management process with emphasis on network devices (such as Cisco VIRL) or individual network policies (such as Propane). [Continues.]</div

Vers une utilisation de la diversité de chemins dans l'internet

In this thesis we consider a new service where carriers offer additional routes to their customers (w.r.t. to the BGP default route) as a free or value-added service. These alternate routes can be used by customers to optimize their communications, by bypassing some congested points in the Internet (e.g. a “tussled” peeringpoints), to help them to meet their traffic engineering objectives (better delays etc.) or just for robustness purposes (e.g, shift to a disjoint alternate route if needed). First we propose a simple architecture that allows a network service provider to benefit from the diversity it currently receives. Then we extend this architecture in order to make the propagation of the Internet path diversity possible, not only to direct neighbors but also to their neighbors and so on. We take advantage of this advance to relax the route selection processes of autonomous systems in order to make them be able to set up new routing paradigms. Nevertheless announcing additional paths can lead to scalability issues, so each carrier could receive more paths than what it could manage. We quantify this issue and we underline easy adaptations and small path filterings which make the number of paths drop to a manageable amount. Last but not least we set up an auction-type route allocation framework, which gives to network service providers the opportunities first to propagate to their neighbors only the paths the said neighbors are interested in and second to leverage a new routing selection paradigm based on commercial agreements and negotiationsNous considérons, dans cette thèse, un nouveau service par lequel les opérateurs de télécommunications offrent des routes supplémentaires à leurs clients (en plus de la route par défaut) comme un service gratuit ou à valeur ajoutée. Ces routes supplémentaires peuvent être utilisées par des clients afin d’optimiser leurs communications, en outrepassant des points de congestion d’Internet, ou les aider à atteindre leurs objectifs d’ingénierie de trafic (meilleurs délais etc.) ou dans un but de robustesse. Nous proposons d’abord une architecture simple permettant à un opérateur de télécommunication de bénéficier de la diversité de chemin qu’il reçoit déjà. Nous étendons ensuite cette architecture afin de rendre possible la propagation de cette diversité de chemin, non seulement aux voisins directs mais aussi, de proche en proche, aux autres domaines. Nous profitons de cette occasion pour relaxer la sélection des routes des différents domaines afin de leur permettre de mettre en place de nouveaux paradigmes de routage. Néanmoins, annoncer des chemins additionnels peut entrainer des problèmes de passage à l’échelle car chaque opérateur peut potentiellement recevoir plus de chemins que ce qu’il peut gérer. Nous quantifions ce problème et mettons en avant des modifications et filtrages simples permettant de réduire ce nombre à un niveau acceptable. En dernier, nous proposons un processus, inspiré des ventes aux enchères, permettant aux opérateurs de propager aux domaines voisins seulement les chemins qui intéressent les dits voisins. De plus, ce processus permet de mettre en avant un nouveau paradigme de propagation de routes, basé sur des négociations et accords commerciau

Rethinking Routing and Peering in the era of Vertical Integration of Network Functions

Content providers typically control the digital content consumption services and are getting the most revenue by implementing an all-you-can-eat model via subscription or hyper-targeted advertisements. Revamping the existing Internet architecture and design, a vertical integration where a content provider and access ISP will act as unibody in a sugarcane form seems to be the recent trend. As this vertical integration trend is emerging in the ISP market, it is questionable if existing routing architecture will suffice in terms of sustainable economics, peering, and scalability. It is expected that the current routing will need careful modifications and smart innovations to ensure effective and reliable end-to-end packet delivery. This involves new feature developments for handling traffic with reduced latency to tackle routing scalability issues in a more secure way and to offer new services at cheaper costs. Considering the fact that prices of DRAM or TCAM in legacy routers are not necessarily decreasing at the desired pace, cloud computing can be a great solution to manage the increasing computation and memory complexity of routing functions in a centralized manner with optimized expenses. Focusing on the attributes associated with existing routing cost models and by exploring a hybrid approach to SDN, we also compare recent trends in cloud pricing (for both storage and service) to evaluate whether it would be economically beneficial to integrate cloud services with legacy routing for improved cost-efficiency. In terms of peering, using the US as a case study, we show the overlaps between access ISPs and content providers to explore the viability of a future in terms of peering between the new emerging content-dominated sugarcane ISPs and the healthiness of Internet economics. To this end, we introduce meta-peering, a term that encompasses automation efforts related to peering – from identifying a list of ISPs likely to peer, to injecting control-plane rules, to continuous monitoring and notifying any violation – one of the many outcroppings of vertical integration procedure which could be offered to the ISPs as a standalone service

Strategies for internet route control: past, present and future

Uno de los problemas más complejos en redes de computadores es el de proporcionar garantías de calidad y confiabilidad a las comunicaciones de datos entre entidades que se encuentran en dominios distintos. Esto se debe a un amplio conjunto de razones -- las cuales serán analizadas en detalle en esta tesis -- pero de manera muy breve podemos destacar: i) la limitada flexibilidad que presenta el modelo actual de encaminamiento inter-dominio en materia de ingeniería de tráfico; ii) la naturaleza distribuida y potencialmente antagónica de las políticas de encaminamiento, las cuales son administradas individualmente y sin coordinación por cada dominio en Internet; y iii) las carencias del protocolo de encaminamiento inter-dominio utilizado en Internet, denominado BGP (Border Gateway Protocol).El objetivo de esta tesis, es precisamente el estudio y propuesta de soluciones que permitan mejorar drásticamente la calidad y confiabilidad de las comunicaciones de datos en redes conformadas por múltiples dominios.Una de las principales herramientas para lograr este fin, es tomar el control de las decisiones de encaminamiento y las posibles acciones de ingeniería de tráfico llevadas a cabo en cada dominio. Por este motivo, esta tesis explora distintas estrategias de como controlar en forma precisa y eficiente, tanto el encaminamiento como las decisiones de ingeniería de tráfico en Internet. En la actualidad este control reside principalmente en BGP, el cual como indicamos anteriormente, es uno de los principales responsables de las limitantes existentes. El paso natural sería reemplazar a BGP, pero su despliegue actual y su reconocida operatividad en muchos otros aspectos, resultan claros indicadores de que su sustitución (ó su posible evolución) será probablemente gradual. En este escenario, esta tesis propone analizar y contribuir con nuevas estrategias en materia de control de encaminamiento e ingeniería de tráfico inter-dominio en tres marcos temporales distintos: i) en la actualidad en redes IP; ii) en un futuro cercano en redes IP/MPLS (MultiProtocol Label Switching); y iii) a largo plazo en redes ópticas, modelando así una evolución progresiva y realista, facilitando el reemplazo gradual de BGP.Más concretamente, este trabajo analiza y contribuye mediante: - La propuesta de estrategias incrementales basadas en el Control Inteligente de Rutas (Intelligent Route Control, IRC) para redes IP en la actualidad. Las estrategias propuestas en este caso son de carácter incremental en el sentido de que interaccionan con BGP, solucionando varias de las carencias que éste presenta sin llegar a proponer aún su reemplazo. - La propuesta de estrategias concurrentes basadas en extender el concepto del PCE (Path Computation Element) proveniente del IETF (Internet Engineering Task Force) para redes IP/MPLS en un futuro cercano. Las estrategias propuestas en este caso son de carácter concurrente en el sentido de que no interaccionan con BGP y pueden ser desplegadas en forma paralela. En este caso, BGP continúa controlando el encaminamiento y las acciones de ingeniería de tráfico inter-dominio del tráfico IP, pero el control del tráfico IP/MPLS se efectúa en forma independiente de BGP mediante los PCEs.- La propuesta de estrategias que reemplazan completamente a BGP basadas en la incorporación de un nuevo agente de control, al cual denominamos IDRA (Inter-Domain Routing Agent). Estos agentes proporcionan un plano de control dedicado, físicamente independiente del plano de datos, y con gran capacidad computacional para las futuras redes ópticas multi-dominio.Los resultados expuestos aquí validan la efectividad de las estrategias propuestas, las cuales mejoran significativamente tanto la concepción como la performance de las actuales soluciones en el área de Control Inteligente de Rutas, del esperado PCE en un futuro cercano, y de las propuestas existentes para extender BGP al área de redes ópticas.One of the most complex problems in computer networks is how to provide guaranteed performance and reliability to the communications carried out between nodes located in different domains. This is due to several reasons -- which will be analyzed in detail in this thesis -- but in brief, this is mostly due to: i) the limited capabilities of the current inter-domain routing model in terms of Traffic Engineering (TE); ii) the distributed and potentially conflicting nature of policy-based routing, where routing policies are managed independently and without coordination among domains; and iii) the clear limitations of the inter-domain routing protocol, namely, the Border Gateway Protocol (BGP). The goal of this thesis is precisely to study and propose solutions allowing to drastically improve the performance and reliability of inter-domain communications. One of the most important tools to achieve this goal, is to control the routing and TE decisions performed by routing domains. Therefore, this thesis explores different strategies on how to control such decisions in a highly efficient and accurate way. At present, this control mostly resides in BGP, but as mentioned above, BGP is in fact one of the main causes of the existing limitations. The natural next-step would be to replace BGP, but the large installed base at present together with its recognized effectiveness in other aspects, are clear indicators that its replacement (or its possible evolution) will probably be gradually put into practice.In this framework, this thesis proposes to to study and contribute with novel strategies to control the routing and TE decisions of domains in three different time frames: i) at present in IP multi-domain networks; ii) in the near-future in IP/MPLS (MultiProtocol Label Switching) multi- domain networks; and iii) in the future optical Internet, modeling in this way a realistic and progressive evolution, facilitating the gradual replacement of BGP.More specifically, the contributions in this thesis can be summarized as follows. - We start by proposing incremental strategies based on Intelligent Route Control (IRC) solutions for IP networks. The strategies proposed in this case are incremental in the sense that they interact with BGP, and tackle several of its well-known limitations. - Then, we propose a set of concurrent route control strategies for MPLS networks, based on broadening the concept of the Path Computation Element (PCE) coming from the IETF (Internet Engineering Task Force). Our strategies are concurrent in the sense that they do not interact directly with BGP, and they can be deployed in parallel. In this case, BGP still controlls the routing and TE actions concerning regular IP-based traffic, but not how IP/MPLS paths are routed and controlled. These are handled independently by the PCEs.- We end with the proposal of a set of route control strategies for multi-domain optical networks, where BGP has been completely replaced. These strategies are supported by the introduction of a new route control element, which we named Inter-Domain Routing Agent (IDRA). These IDRAs provide a dedicated control plane, i.e., physically independent from the data plane, and with high computational capacity for future optical networks.The results obtained validate the effectiveness of the strategies proposed here, and confirm that our proposals significantly improve both the conception and performance of the current IRC solutions, the expected PCE in the near-future, as well as the existing proposals about the optical extension of BGP.Postprint (published version

Alternative revenue sources for Internet service providers

The Internet has evolved from a small research network towards a large globally interconnected network. The deregulation of the Internet attracted commercial entities to provide various network and application services for profit. While Internet Service Providers (ISPs) offer network connectivity services, Content Service Providers (CSPs) offer online contents and application services. Further, the ISPs that provide transit services to other ISPs and CSPs are known as transit ISPs. The ISPs that provide Internet connections to end users are known as access ISPs. Though without a central regulatory body for governing, the Internet is growing through complex economic cooperation between service providers that also compete with each other for revenues. Currently, CSPs derive high revenues from online advertising that increase with content popularity. On other hand, ISPs face low transit revenues, caused by persistent declines in per-unit traffic prices, and rising network costs fueled by increasing traffic volumes. In this thesis, we analyze various approaches by ISPs for sustaining their network infrastructures by earning extra revenues. First, we study the economics of traffic attraction by ISPs to boost transit revenues. This study demonstrates that traffic attraction and reaction to it redistribute traffic on links between Autonomous Systems (ASes) and create camps of winning, losing and neutral ASes with respect to changes in transit payments. Despite various countermeasures by losing ASes, the traffic attraction remains effective unless ASes from the winning camp cooperate with the losing ASes. While our study shows that traffic attraction has a solid potential to increase revenues for transit ISPs, this source of revenues might have negative reputation and legal consequences for the ISPs. Next, we look at hosting as an alternative source of revenues and examine hosting of online contents by transit ISPs. Using real Internet-scale measurements, this work reports a pervasive trend of content hosting throughout the transit hierarchy, validating the hosting as a prominent source of revenues for transit ISPs. In our final work, we consider a model where access ISPs derive extra revenues from online advertisements (ads). Our analysis demonstrates that the ad-based revenue model opens a significant revenue potential for access ISPs, suggesting its economic viability.This work has been supported by IMDEA Networks Institute.Programa Oficial de Doctorado en Ingeniería TelemáticaPresidente: Jordi Domingo-Pascual.- Vocal: Víctor López Álvarez.-Secretario: Alberto García Martíne

Improving Pan-African research and education networks through traffic engineering: A LISP/SDN approach

The UbuntuNet Alliance, a consortium of National Research and Education Networks (NRENs) runs an exclusive data network for education and research in east and southern Africa. Despite a high degree of route redundancy in the Alliance's topology, a large portion of Internet traffic between the NRENs is circuitously routed through Europe. This thesis proposes a performance-based strategy for dynamic ranking of inter-NREN paths to reduce latencies. The thesis makes two contributions: firstly, mapping Africa's inter-NREN topology and quantifying the extent and impact of circuitous routing; and, secondly, a dynamic traffic engineering scheme based on Software Defined Networking (SDN), Locator/Identifier Separation Protocol (LISP) and Reinforcement Learning. To quantify the extent and impact of circuitous routing among Africa's NRENs, active topology discovery was conducted. Traceroute results showed that up to 75% of traffic from African sources to African NRENs went through inter-continental routes and experienced much higher latencies than that of traffic routed within Africa. An efficient mechanism for topology discovery was implemented by incorporating prior knowledge of overlapping paths to minimize redundancy during measurements. Evaluation of the network probing mechanism showed a 47% reduction in packets required to complete measurements. An interactive geospatial topology visualization tool was designed to evaluate how NREN stakeholders could identify routes between NRENs. Usability evaluation showed that users were able to identify routes with an accuracy level of 68%. NRENs are faced with at least three problems to optimize traffic engineering, namely: how to discover alternate end-to-end paths; how to measure and monitor performance of different paths; and how to reconfigure alternate end-to-end paths. This work designed and evaluated a traffic engineering mechanism for dynamic discovery and configuration of alternate inter-NREN paths using SDN, LISP and Reinforcement Learning. A LISP/SDN based traffic engineering mechanism was designed to enable NRENs to dynamically rank alternate gateways. Emulation-based evaluation of the mechanism showed that dynamic path ranking was able to achieve 20% lower latencies compared to the default static path selection. SDN and Reinforcement Learning were used to enable dynamic packet forwarding in a multipath environment, through hop-by-hop ranking of alternate links based on latency and available bandwidth. The solution achieved minimum latencies with significant increases in aggregate throughput compared to static single path packet forwarding. Overall, this thesis provides evidence that integration of LISP, SDN and Reinforcement Learning, as well as ranking and dynamic configuration of paths could help Africa's NRENs to minimise latencies and to achieve better throughputs

Proactive techniques for correct and predictable Internet routing

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, February 2006.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 185-193).The Internet is composed of thousands of autonomous, competing networks that exchange reachability information using an interdomain routing protocol. Network operators must continually reconfigure the routing protocols to realize various economic and performance goals. Unfortunately, there is no systematic way to predict how the configuration will affect the behavior of the routing protocol or to determine whether the routing protocol will operate correctly at all. This dissertation develops techniques to reason about the dynamic behavior of Internet routing, based on static analysis of the router configurations, before the protocol ever runs on a live network. Interdomain routing offers each independent network tremendous flexibility in configuring the routing protocols to accomplish various economic and performance tasks. Routing configurations are complex, and writing them is similar to writing a distributed program; the (unavoidable) consequence of configuration complexity is the potential for incorrect and unpredictable behavior. These mistakes and unintended interactions lead to routing faults, which disrupt end-to-end connectivity. Network operators writing configurations make mistakes; they may also specify policies that interact in unexpected ways with policies in other networks.(cont.) To avoid disrupting network connectivity and degrading performance, operators would benefit from being able to determine the effects of configuration changes before deploying them on a live network; unfortunately, the status quo provides them no opportunity to do so. This dissertation develops the techniques to achieve this goal of proactively ensuring correct and predictable Internet routing. The first challenge in guaranteeing correct and predictable behavior from a routing protocol is defining a specification for correct behavior. We identify three important aspects of correctness-path visibility, route validity, and safety-and develop proactive techniques for guaranteeing that these properties hold. Path visibility states that the protocol disseminates information about paths in the topology; route validity says that this information actually corresponds to those paths; safety says that the protocol ultimately converges to a stable outcome, implying that routing updates actually correspond to topological changes. Armed with this correctness specification, we tackle the second challenge: analyzing routing protocol configurations that may be distributed across hundreds of routers.(cont.) We develop techniques to check whether a routing protocol satisfies the correctness specification within a single independently operated network. We find that much of the specification can be checked with static configuration analysis alone. We present examples of real-world routing faults and propose a systematic framework to classify, detect, correct, and prevent them. We describe the design and implementation of rcc ("router configuration checker"), a tool that uses static configuration analysis to enable network operators to debug configurations before deploying them in an operational network. We have used rcc to detect faults in 17 different networks, including several nationwide Internet service providers (ISPs). To date, rcc has been downloaded by over seventy network operators. A critical aspect of guaranteeing correct and predictable Internet routing is ensuring that the interactions of the configurations across multiple networks do not violate the correctness specification. Guaranteeing safety is challenging because each network sets its policies independently, and these policies may conflict. Using a formal model of today's Internet routing protocol, we derive conditions to guarantee that unintended policy interactions will never cause the routing protocol to oscillate.(cont.) This dissertation also takes steps to make Internet routing more predictable. We present algorithms that help network operators predict how a set of distributed router configurations within a single network will affect the flow of traffic through that network. We describe a tool based on these algorithms that exploits the unique characteristics of routing data to reduce computational overhead. Using data from a large ISP, we show that this tool correctly computes BGP routing decisions and has a running time that is acceptable for many tasks, such as traffic engineering and capacity planning.by Nicholas Greer Feamster.Ph.D

From the edge to the core : towards informed vantage point selection for internet measurement studies

Since the early days of the Internet, measurement scientists are trying to keep up with the fast-paced development of the Internet. As the Internet grew organically over time and without build-in measurability, this process requires many workarounds and due diligence. As a result, every measurement study is only as good as the data it relies on. Moreover, data quality is relative to the research question—a data set suitable to analyze one problem may be insufficient for another. This is entirely expected as the Internet is decentralized, i.e., there is no single observation point from which we can assess the complete state of the Internet. Because of that, every measurement study needs specifically selected vantage points, which fit the research question. In this thesis, we present three different vantage points across the Internet topology— from the edge to the Internet core. We discuss their specific features, suitability for different kinds of research questions, and how to work with the corresponding data. The data sets obtained at the presented vantage points allow us to conduct three different measurement studies and shed light on the following aspects: (a) The prevalence of IP source address spoofing at a large European Internet Exchange Point (IXP), (b) the propagation distance of BGP communities, an optional transitive BGP attribute used for traffic engineering, and (c) the impact of the global COVID-19 pandemic on Internet usage behavior at a large Internet Service Provider (ISP) and three IXPs.Seit den frühen Tagen des Internets versuchen Forscher im Bereich Internet Measu- rement, mit der rasanten Entwicklung des des Internets Schritt zu halten. Da das Internet im Laufe der Zeit organisch gewachsen ist und nicht mit Blick auf Messbar- keit entwickelt wurde, erfordert dieser Prozess eine Meg Workarounds und Sorgfalt. Jede Measurement Studie ist nur so gut wie die Daten, auf die sie sich stützt. Und Datenqualität ist relativ zur Forschungsfrage - ein Datensatz, der für die Analyse eines Problems geeiget ist, kann für ein anderes unzureichend sein. Dies ist durchaus zu erwarten, da das Internet dezentralisiert ist, d. h. es gibt keinen einzigen Be- obachtungspunkt, von dem aus wir den gesamten Zustand des Internets beurteilen können. Aus diesem Grund benötigt jede Measurement Studie gezielt ausgewählte Beobachtungspunkte, die zur Forschungsfrage passen. In dieser Arbeit stellen wir drei verschiedene Beobachtungspunkte vor, die sich über die gsamte Internet-Topologie erstrecken— vom Rand bis zum Kern des Internets. Wir diskutieren ihre spezifischen Eigenschaften, ihre Eignung für verschiedene Klas- sen von Forschungsfragen und den Umgang mit den entsprechenden Daten. Die an den vorgestellten Beobachtungspunkten gewonnenen Datensätze ermöglichen uns die Durchführung von drei verschiedenen Measurement Studien und damit die folgenden Aspekte zu beleuchten: (a) Die Prävalenz von IP Source Address Spoofing bei einem großen europäischen Internet Exchange Point (IXP), (b) die Ausbreitungsdistanz von BGP-Communities, ein optionales transitives BGP-Attribut, das Anwendung im Bereich Traffic-Enigneering findet sowie (c) die Auswirkungen der globalen COVID- 19-Pandemie auf das Internet-Nutzungsverhalten an einem großen Internet Service Provider (ISP) und drei IXPs