Layer 1-informed Internet Topology Measurement

Understanding the Internet’s topological structure continues to be fraught with challenges. In this paper, we investigate the hypothesis that physical maps of service provider infras-tructure can be used to effectively guide topology discov-ery based on network layer TTL-limited measurement. The goal of our work is to focus layer 3-based probing on broadly identifying Internet infrastructure that has a fixed geographic location such as POPs, IXPs and other kinds of hosting fa-cilities. We begin by comparing more than 1.5 years of TTL-limited probe data from the Ark [25] project with maps of service provider infrastructure from the Internet Atlas [15] project. We find that there are substantially more nodes and links identified in the service provider map data ver-sus the probe data. Next, we describe a new method for probe-based measurement of physical infrastructure called POPsicle that is based on careful selection of probe source-destination pairs. We demonstrate the capability of our method through an extensive measurement study using ex-isting “looking glass ” vantage points distributed throughout the Internet and show that it reveals 2.4 times more phys-ical node locations versus standard probing methods. To demonstrate the deployability of POPsicle we also conduct tests at an IXP. Our results again show that POPsicle can identify more physical node locations compared with stan-dard layer 3 probes, and through this deployment approach it can be used to measure thousands of networks world wide

Growth Analysis of a Large ISP

We present a time-series analysis of Cogent’s inter-continental network. The analysis is based on descriptions of Cogent’s routers and their interfaces, collected each week for more than one year. These descriptions are collected from public reverse DNS records, which we cross-validate using iffinder, a full Internet scan, and limited ground truth data provided by Cogent. For example, our dataset, which we make available to the research community, shows that while the number of Cogent routers grew by approximately 11.3 each week, the average number of interfaces per router, and the effective diameter of the inferred network remained stable over the same period. Our collected dataset includes information about interface types, port identifications, router locations, peer and customer attachments, and more