Understading Multiple Origin AS Conflicts

Internet routing problems are often difficult to detect and diagnose because one address prefix can be originated by multiple ASes. There is, however, no comprehensive analysis on the causes of Multiple Origin AS (MOAS) conflicts. In this paper, we study the characteristics of MOAS conflicts and compare them with those from 10 years ago. We also provide an in-depth examination of four MOAS causes--IXP, anycast, false origin AS, and origin-AS transition. Furthermore, we propose two heuristics to identify MOAS conflicts caused by false origin ASes and origin-AS transitions. The findings from our study and proposed heuristics can help us design effective mechanisms to distinguish legitimate MOAS conflicts from illegitimate ones, thus improving the reliability and security of Internet routing