Wide area redirection of dynamic content by Internet data centers

Traditional approaches to mirroring, caching, and content distribution have an underlying assumption that minimizing network hop count minimizes client latency. However, with uncongested backbones and potentially high-latency service times for dynamic content, such techniques are of limited effectiveness. We present an architecture in which dispatchers at an overloaded Internet data center (IDC) redirect requests for dynamic content to a geographically remote but less loaded IDC. We show with both analytical modeling as well as testbed experiments that the delay savings of redirecting requests to a lightly loaded IDC can far outweigh the overhead in interIDC network latency. Consequently, client end-to-end delays are significantly reduced without requiring modifications to clients, servers, or DNS.