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There is now a CONTENT FREEZE for Mercury while we switch to a new platform. It began on Friday, March 10 at 6pm and will end on Wednesday, March 15 at noon. No new content can be created during this time, but all material in the system as of the beginning of the freeze will be migrated to the new platform, including users and groups. Functionally the new site is identical to the old one. webteam@gatech.edu
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We study the scheduling policies for high-speed communication networks with time varying traffic patterns. We model such networks as open multiclass queueing networks operating in a slowly changing environment.
We assume that there are finite environment states and the changing environment is modeled as a general stochastic process which takes discrete values. At each state of the environment, the network operates as a queueing network where each server may serve multiple classes of customers. In this study, we establish a framework to search for asymptotically optimal scheduling policies for such queueing networks. We first show that open queueing networks in a slowly changing environment can be approximated by their fluid analog, stochastic fluid models, when the network speed increases. Given a solution of the stochastic fluid model, we provide a method to derive suitable scheduling policies for the original queueing networks. We further show that the queueing networks operating under the derived policies converge to the corresponding stochastic fluid model . This result implies that the derived scheduling policies are asymptotically optimal if the given stochastic fluid model solution is optimal. We also study a stochastic fluid model to investigate the optimal resource allocation policies of Web servers serving heterogeneous classes where the Web servers may be overloaded and operate under Quality of Service contracts.
