Frequency Asked Questions
  1. How often is AS Rank updated?
    We aim for a monthly update update to the topological data. We update the Organization name and country roughly every three months. But the project has no dedicated funding, so it is best effort.
  2. How are ASes ranked?
    We rank ASNs by the number of ASes in the customer cone. To break ties, we sort by the number of prefixes if the number of IP addresses in the customer cone, then the global AS degree (number of AS neighbord), and finally by transit degree. Formally, an AS's rank is equal to one (1) more than the number of higher-ranked ASes (so that the highest ranked AS has rank 1).
  3. How is prefix and address customer cone defined? How does this affect overall ranking?
    An AS's prefix-level customer cone is the union of the prefixes announced by all ASes in its AS customer cone (which by definition includes the AS itself). The address-level customer cone is the set of addresses covered by the prefixes in the prefix-level customer cone.
  4. How do you compute customer cones?
    We describe our algorithm for computing the customer cone here and (in excruciating detail) in our IMC 2013 paper: "AS Relationships, Customer Cones, and Validation".

    Our inference algorithm relies on public BGP data from RouteViews and RIPE RIS. Importantly, per the figure, we do not infer an AS's customer cone based on paths observed directly from that AS. Rather, we use paths observed from the peers and providers of the AS in question. The reason for this filtering is that an AS selectively announces paths: to its customers, it may announce everything, but to its "upstream" providers or peers ASes, it will announce only paths to its customers. Thus, we need to make sure we observe a path through an AS's provider or peer in order to infer the destination prefix (and its origin AS) as in the customer cone of that AS. to its providers and peer ASes.

  5. How do I improve my AS ranking?
    Our inference algorithm relies on public BGP data from RouteViews and RIPE RIS. The best way to increase the number of ASes we can observe in your customer cone is to make those ASes more visible to these public route collector projects. That is, announce more AS paths to your providers or peers who contribute feeds to RouteViews or RIPE NCC RIS.

  6. Can you correct an inaccurate inference if I provide a correction?
    We can change an inference for an existing interconnection relationship if you provide us ground truth, but we cannot add interconnections that we do not observe in BGP. In other words, we can update our Operator Feedback database with a list of peers and customers you provide, but that does not guarantee that the interconnections will appear in our observed set of relationships -- only that if the interconnection does appear, it will match the relationship you provided.

    We are open to other ideas to improve the accuracy of our inferences, but sustainability of the project requires an automated, scalable method to infer the cone based on publicly available data.

    Please email comments or questions to