Optimizing Internet Transit Routing for Content Delivery Networks

Content delivery networks (CDNs) maintain multiple transit routes from content distribution servers to eyeball ISP networks which provide Internet connectivity to end users. Due to the dynamics of varying performance and pricing on transit routes, CDNs need to implement a transit route selection strategy to optimize performance and cost tradeoffs. In this paper, we formalize the transit routing problem using a multi-attribute objective function to simultaneously optimize end-to-end performance and cost. Our approach allows CDNs to navigate the cost and performance tradeoff in transit routing through a single control knob. We evaluate our approach using real-world measurements from CDN servers located at 19 geographically distributed Internet exchange points. Using our approach, CDNs can reduce transit costs on average by 57% without sacrificing performance.