How Cloud Traffic Goes Hiding: A Study of Amazon's Peering Fabric

The growing demand for an ever-increasing number of cloud services is profoundly transforming the Internet's interconnection or peering ecosystem, and one example is the emergence of "virtual private interconnections (VPIs)". However, due to the underlying technologies, these VPIs are not publicly visible and traffic traversing them remains largely hidden as it bypasses the public Internet. In particular, existing techniques for inferring Internet interconnections are unable to detect these VPIs and are also incapable of mapping them to the physical facility or geographic region where they are established. In this paper, we present a third-party measurement study aimed at revealing all the peerings between Amazon and the rest of the Internet. We describe our technique for inferring these peering links and pay special attention to inferring the VPIs associated with this largest cloud provider. We also present and evaluate a new method for pinning (i.e., geo-locating) each end of the inferred interconnections or peering links. Our study provides a first look at Amazon's peering fabric. In particular, by grouping Amazon's peerings based on their key features, we illustrate the specific role that each group plays in how Amazon peers with other networks.