A Platform for End-Host-based Active Measurements on the Internet

Abstract

The size and complexity of the Internet grow continuously. Billions of interconnected devices communicate over this large network of networks, transporting a steadily increasing amount of traffic. As the Internet grows, the importance of it as a vital telecommunications infrastructure is increasing as well. Given its role and importance, it is somewhat worrisome that an accurate status of the operational state of the Internet cannot reasonably be obtained. Many interesting questions about the Internet and its performance are difficult to answer and it would require a large number of vantage points to answer some of them. There is no complete "map"' of the Internet and when problems occur, it is often difficult to identify their source, in particular in an automated fashion. Measurement platforms could continuously monitor vital functions of the Internet and help to detect, locate and solve problems in the network. There is a great interest from Internet Service Providers (ISPs), end-users, and content providers to be alerted quickly if something is not working as expected, to pinpoint problems, and even to fix a problem before it manifests in some kind of performance problem or outage. Therefore, it would be beneficial to have a standardized way to execute distributed measurements on the Internet. Multiple organizations and projects, for example the Large-Scale Measurement of Broadband Performance (LMAP) working group of the Internet Engineering Task Force (IETF) or the EU project mPlane, worked and still work on the standardization of measurement platforms. Those efforts make it possible to coordinate and execute comparable measurements on distributed probes, using common interfaces that allow different vendors of probes and other components of such measurement platforms to interoperate. GLIMPSE (Global Internet Monitoring and Probing System) is a concrete example of a platform for active measurement campaigns, which was developed alongside currently evolving standards. This platform can schedule measurement campaigns on a large number of probes deployed on common devices of end-users. The data produced by these measurements can be used to find and analyze anomalies in the Internet. This dissertation gives an overview of standardization efforts, tools, and projects in the field of platforms for active measurements on the Internet. GLIMPSE, a platform developed as part of this dissertation, is used to describe the characteristics, design, implementation and limitations of such platforms. A glimpse into the possible research and the obtainable results is given by looking at real measurement campaigns realized with this system. One such campaign shows for example how a popular method widely used by end-users for measuring network access rates at home is flawed. GLIMPSE was build at a time of active standardization in the field of large-scale measurement platforms. To give researchers and developers data and advice as a basis to decide if it is worth to use still evolving pre-standards in their work, an analysis of the document process within the IETF was performed. Also, the main challenges when designing and implementing a platform for measurements with a large number of end-users have been identified and analyzed. GLIMPSE probes rely solely on active measurements. In order to showcase the research potential of passive measurements on end-device probes, an analysis of broadcast and multicast traffic captured passively on such devices has been carried out. The results of this research was brought to the attention of the Internet Area working group of the IETF and has been adopted by that group as a working group item at the time of this writing. The respective Internet draft lists considerations for broadcast and multicast protocol designers.

In dieser Dissertation wurden Plattformen für aktive Messungen im Internet untersucht. Eine Beschreibung bereits vorhandener Forschungsarbeiten und insbesondere Bemühungen zur Standardisierung solcher Plattformen geben einen Überblick über den aktuellen Stand der Forschung. Durch eine Zusammenfassung der aktuell verfügbaren Plattformen zeigt sich, dass es diese sich in vielen Aspekten unterscheiden, wie etwa die Art der Implementierung (als Software- Pakete oder vorinstalliert auf Hardware), dem Grad der Freiheit für den Benutzer (können Benutzer oder nur die Plattform-Betreiber beziehungsweise Forscher Messungen durchführen) und die verwendeten Messmethoden und deren Erweiterbarkeit. Basierend auf den Arbeiten des EU-geförderten Forschungsprojektes mPlane und den vorläufigen Standards der Large-Scale Measurement of Broadband Performance (LMAP) Arbeitsgruppe der Internet Engineering Task Force (IETF), wurde für diese Dissertation GLIMPSE (Global Internet Monitoring and Probing System) entwickelt. Diese Plattform für aktive Messungen ist speziell für den Einsatz bei Endnutzern im Heimnetzwerk konzipiert und entwickelt worden. Neben einer detaillierten Beschreibung des Systems und der implementierten Messmethoden sind außerdem die Ergebnisse mehrerer Messkampagnen dargestellt. Es zeigt sich zum Einen, welche Art von Messungen durchgeführt und welche Anomalien dabei entdeckt werden können. Zum Anderen wird aber auch deutlich, dass Messkampagnen langfristig und auf einer großen Anzahl von verteilten Punkten im Internet durchgeführt werden müssen, um Unregelmäßigkeit frühzeitig zu erkennen. GLIMPSE befasst sich ausschließlich mit aktiven Messungen. Um das Forschungspotenzial von passiven Messungen auf Endgeräten zu demonstrieren, wurde eine Analyse der passiv empfangenen Broadcast- und Multicastdaten auf solchen Geräten durchgeführt. Die Ergebnisse dieser Forschung wurde in die Internet Area Arbeitsgruppe der IETF eingebracht und als Dokument der Arbeitsgruppe angenommen. Dieser sogenannte Internet Draft gibt Hinweise und Beispiele für Entwickler, die Broadcast- und Multicastprotokolle designen und hat das Ziel, zum RFC zu werden.