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Further Topics in Measurement

DNS

The Domain Name System is nowadays being (mis)used by CDNs to map user resquests to appropriate servers. DNS is therefore the central mechanism through which the location from which content is obtained is being chosen. Despite its widespread use for several decades, the behavior of DNS deployment within ISP networks is still poorly understood. In this work, we measure the performance of DNS from a large set of vantage points inside commercial ISPs, and analyze its consequences on the CDN server selection mechanism.

Mapping the Internet Content Infrastructure

Content is king in today's Internet. Most of the traffic exchanged in the Internet relates to content whose popularity changes very fast over time. Due to the large amount of traffic that has to be delivered, content delivery platforms are delivering content from multiple locations, typically data-centers, as well as deployed caches deep within ISP networks to go around network bottlenecks. To better understand the way content is Before being able to understand how dynamic Internet content is, we need to find out where the servers that host it are, and how different applications that manage content decide how to map content to their servers. In this work, we rely on active measurements to map the infrastructure hosting content in the Internet.

Geolocation

IP Geolocation consists in finding the geographic location of an IP address in the Internet. There are two methods: passive (geolocation databases) and active (active measurements). Geolocation databases are known to have limited accuracy, while active measurements place burden on the network and require distributed measurements infrastructures. Both methods have limited accuracy, but their actual accuracy has been understudied in the literature, especially for geolocation databases. In this work, we investigate the accuracy of geolocation databases based on ground truth information, and find that their accuracy is very limited at the country-level.

Selected Publications

IP Geolocation Databases: Unreliable?
Citation key PUKDG-IGDU-11
Author Poese, Ingmar and Uhlig, Steve and Kaafar, Mohamed Ali and Donnet, Benoit and Gueye, Bamba
Pages 53–56
Year 2011
ISSN 0146-4833
Journal ACM SIGCOMM Computer Communication Review (CCR)
Volume 41
Number 2
Month April
Note editorial zone
Abstract The most widely used technique for IP geolocation consists in building a database to keep the mapping between IP blocks and a geographic location. Several databases are available and are frequently used by many services and web sites in the Internet. Contrary to widespread belief, geolocation databases are far from being as reliable as they claim. In this paper, we conduct a comparison of several current geolocation databases–both commercial and free–to have an insight of the limitations in their usability. First, the vast majority of entries in the databases refer only to a few popular countries (e.g., U.S.). This creates an imbalance in the representation of countries across the IP blocks of the databases. Second, these entries do not reflect the original allocation of IP blocks, nor BGP announcements. In addition, we quantify the accuracy of geolocation databases on a large European ISP based on ground truth information. This is the first study using a ground truth showing that the overly fine granularity of database entries makes their accuracy worse, not better. Geolocation databases can claim country-level accuracy, but certainly not city-level.
Link to publication Link to original publication Download Bibtex entry

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