Inferring POP-Level ISP Topology through End-to-End Delay Measurement

In this paper, we propose a new topology inference technique that aims to reveals how ISPs deploy their layer two and three networks at the POP level, without relying on ISP core network information such as router hops and domain names. This is because, even though most of previous works in this field leverage core network information to infer ISP topologies, some of our measured ISPs filter ICMP packets and do not allow us to access core network information through traceroute. And, several researchers point out that such information is not always reliable. So, to infer ISP core network topology without relying on ISP releasing information, we deploy systems to measure end-to-end communication delay between residential users, and map the collected delay and corresponding POP-by-POP paths. In our inference process, we introduce assumptions about how ISPs tend to deploy their layer one and two networks. To validate our methodology, we measure end-to-end communication delay of four nationwide ISPs between thirteen different cities in Japan and infer their POP-level topologies.