Service Differentiation in Multi-tier Application Architectures

Enterprise networks, such as back-end offices, data centers or web server farms support multiple services and are typically architected in multiple computing tiers. In Service-Oriented-Architecture (SOA) environments, one tier is used for, say, offloading the CPU-intensive XML processing. The business logic is then implemented in a separate tier. The offload tier is typically implemented as a cluster of (potentially virtual) middle-ware appliances. Service differentiation in enterprise networks addresses the issues of managing the enterprise network resources in order to achieve desired performance objectives. In this paper, we define and evaluate via simulations an algorithm that manages allocation of CPU time in the appliance tier, by means of activating and deactivating service domains in the appliance cluster. The main design objective of our algorithm is to overcome the disadvantages of the present static solutions.