Performance evaluation and asymptotics for Content Delivery Networks

Large scale Content Delivery Networks (CDNs) are one of the key components of today´s information infrastructure. This paper proposes and analyzes a simple stochastic model for a file-server system wherein servers can work together, as a pooled resource, to meet individual user requests. In such systems basic questions include: How and where to replicate files? What is the impact of dynamic service allocation across request types, and whether it can provide substantial gains over simpler load balancing policies? What are tradeoffs amongst performance, reliability and recovery costs, and energy? The paper provides both explicit and asymptotic approximations for large systems towards addressing these basic questions.