In inter-domain routing, a packet is not always forwarded along the Autonomous System (AS) level path determined by the BGP routing protocol. This is often called control-plane and data-plane (CD) mismatch, which allows for flexible traffic control, but also leads to operation and security issues. We systematically analyze this phenomenon with path pairs collected from 128 pairs of vantage points over more than 5 years, and use multiple IP-to-AS mapping methods to compare CD paths. What is interesting is that, working at such a large scale in turn helps us design a novel method to fairly evaluate the accuracy of various existing mapping methods, and further develop a new mapping method, i.e., LearnToCorrect, that can correct more than 70\% mapping errors of the state-of-the-art one. Then we devise to identify real mismatches with LearnToCorrect, and estimate that the real-mismatch ratio in the wild is typically less than 6\%. At last, we use our proposed methods to detect routing security issues, which are previously difficult to accurately find out.

翻译：摘要：在域间路由中，数据包并非始终按照BGP路由协议确定的自治系统（AS）级路径进行转发。这种现象通常被称为控制平面与数据平面（CD）不一致性，它虽然允许灵活流量控制，但也带来了运维与安全问题。我们利用从128对观测点收集的超过5年的路径对，系统分析了该现象，并采用多种IP-AS映射方法对比CD路径。有趣的是，大规模研究促使我们设计了一种新方法，可公平评估现有多种映射方法的准确性，进而开发出新型映射方法LearnToCorrect，该方法能纠正超过70%的最先进映射方法产生的映射错误。随后我们利用LearnToCorrect识别真实的不一致性，并估计实际场景中真实不一致比例通常低于6%。最后，我们运用所提方法检测此前难以准确发现的路由安全问题。