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Effective placement of resources used to support distributed services in the Internet depends on an accurate representation of Internet topology and routing. Representations of autonomous system (AS) level topology derived solely from BGP tables show only a subset of the connections that actually get used. However, in many cases, missing connections can be discovered by simple traceroutes. In addition, the differences between customer-to-provider links, peer-to-peer links, and sibling-to-sibling links are useful distinctions for the resource placement problem which is the focus of our work. Using two complementary mechanisms, we improve the accuracy of an AS forest as a predictor of packet paths. One mechanism uses recent insights that packets flow unidirectionally across customer-provider inter-AS links. Annotations are added to the AS forest to indicate links that appear to be peering versus those that appear to be customer-provider links. The other mechanism provides links between trees by remembering the most recently seen similar traceroute. The paper concludes by applying the annotated AS forest to a problem in resource placement to show that the representation is amenable to computationally inexpensive analysis.