  For a provider of a Content Delivery Network (CDN), the location selection of
mirror servers is a complex optimization problem. Generally, the objective is
to place the nodes centralized such that all customers have convenient access
to the service according to their demands. It is an instance of the k-center
problem, which is proven to be NP-hard. Determining reasonable server locations
directly influences run time effects and future service costs. We model,
simulate, and optimize the properties of a content delivery network.
Specifically, considering the server locations in a network infrastructure with
prioritized customers and weighted connections. A simulation model for the
servers is necessary to analyze the caching behavior in accordance to the
targeted customer requests. We analyze the problem and compare different
optimization strategies. For our simulation, we employ various realistic
scenarios and evaluate several performance indicators. Our new optimization
approach shows a significant improvement. The presented results are generally
applicable to other domains with k-center problems, e.g., the placement of
military bases, the planning and placement of facility locations, or data
mining.
