Measuring path divergence in the Internet

Abstract

Path divergence refers to a situation where a path from source to an intermediate router on a source to destination path may not be a prefix of the source to destination path. Studying path divergence helps us understand various operational characteristics of the underlying network. In this paper, we perform an active measurement study to observe the magnitude, causes, and types of path divergence in the Internet. We observe that most path divergence cases occur due to load balancing routers but policy-based inter domain routing practices also contribute to divergence. We also observe that most routers causing path divergence are positioned in the backbone of the network but routers closer to the sources are causing more number of divergences. Our study combined with peering relationship data between neighboring domains can also point out potential routing anomaly cases in the inter domain routing process in the Internet. Finally, our techniques to trace to intermediate routers can explore new IP addresses, routers, Autonomous Systems (ASes) which can potentially help enrich topology mapping procedure and infer new peering relationships among ASes.