| Summary: | 碩士 === 國立臺灣大學 === 資訊工程學研究所 === 94 === Characterization of Internet paths is important because it helps network operators and researchers better understand how packets travel over the Internet, and allows them to evaluate proposed mechanisms with confidence under realistic network path generating conditions. Some researchers have concluded that shortest path routes are reasonable for studying large-scale behavior of network paths in terms of path length. However, whether shortest path routing is suitable for general network simulations remains an open question.
Motivated by this question, we analyze Internet AS-level paths and find that, although shortest paths and Internet AS-level paths are similar in length, they are very different in the AS-level links traversed. Further examination of the distribution of traffic by shortest paths and Internet AS-level paths shows that the difference persists irrespective of whether representative shortest paths or shortest policy paths are chosen. We find that neither shortest path routing nor shortest policy path routing accurately capture the distribution of traffic generated by Internet AS-level paths.
To facilitate the generation of realistic Internet AS-level paths, we propose a preference-ratio random-walk model that leverages BGP routing tables to obtain preference ratios for the selection of subsequent hops. The results of our evaluations show that the proposed model can characterize Internet AS-level paths effectively.
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