Mobile Content Hosting Infrastructure In China: A View From A Cellular Isp

Internet users are heavily relying on mobile terminals for content access, where the content is hosted and delivered by either third-party infrastructures (e.g., CDNs and clouds) or the content providers' own delivery networks, or both. China has the largest mobile Internet population in a single country, and also has unique local regulations and network policies (e.g. heavy content censorship). The content delivery ecosystem in China, as such, may show great disparity from the western one. Yet, there is little visibility into the content hosting infrastructure in Chinese cellular networks. This paper makes the first step toward filling this gap by analyzing a passive DNS trace that consists of 55 billion DNS logs collected from a national-scale cellular ISP. Our in-depth investigation of the content-related features of major ASes reveals that content objects of popular domains are replicated deep into the examined cellular ISP. On the other hand, as much as 20% of tracking traffic, which is mainly generated by trackers owned US-based companies, goes out of China. Our findings cast useful insights for cellular ISPs, CDNs and Internet policy makers.