Analyzing BGP policies: methodology and tool

Abstract

The robustness of the Internet relies heavily on the robustness of BGP routing. BGP is the glue that holds the Internet together: it is the common language of the routers that interconnect networks or autonomous systems (AS). The robustness of BGP and our ability to manage it effectively is hampered by the limited global knowledge and lack of coordination between autonomous systems. One of the few efforts to develop a globally analyzable and secure Internet is the creation of the Internet routing registries (IRRs). IRRs provide a voluntary detailed repository of BGP policy information. The IRR effort has not reached its full potential because of two reasons: a) extracting useful information is far from trivial, and b) its accuracy of the data is uncertain. In this paper, we develop a methodology and a tool (Nemecis) to extract and infer information from IRR and validate it against BGP routing tables. In addition, using our tool, we quantify the accuracy of the information of IRR. We find that IRR has a lot of inaccuracies, but also contains significant and unique information. Finally, we show that our tool can identify and extract the correct information from IRR discarding erroneous data. In conclusion, our methodology and tool close the gap in the IRR vision for an analyzable Internet repository at the BGP level