CDN interconnection service trial: implementation and analysis

Content delivery service has become a major traffic load on today's Internet, and this has triggered the interest of ISPs in operating their own content delivery networks (CDNs) to optimize Internet traffic considering both content delivery caching and user-network proximity. ISPs, however, are typically regionally bound or network-domain-wise isolated; hence, their CDN gain is somewhat limited. In order to enhance the gain of ISP CDN services to the level of incumbent global CDNs, a CDN interconnection (CDNI) model is introduced by IETF, where local ISP CDN services can be extended among heterogeneous CDNs across network domains. However, despite the multiple benefits of a CDNI system, it is difficult to apply a CDNI service to the current CDN market due to the platform independence. Hence, we introduced a CDNI gateway model that is standard-capable and platform-independent. With the CDNI gateway model, we design and implement a complete CDNI system and conduct a CDNI service trial with three major ISPs in South Korea. To the best of our knowledge, this is the first CDNI service trial complying with the IETF standard achieved by a multi-ISP collaboration. According to the analysis of experimental results from the service trial, we observe that CDNI can reduce content traffic by about 40 percent at the Internet exchange link compared to a legacy CDN system.