Session based access control in Content Delivery Networks in presence of congestion

To ensure probabilistic guarantees on quality of service in Content Delivery Networks (CDN), an access control support is needed that takes into account a proper differentiation of requests and performs session based decisions, managing different types of services and different service phases. In this paper we introduce a CDN architecture with access control capabilities at session aware access routers. We formulate a Markov Modulated Poisson Decision Process for access control that captures the heterogeneity of multimedia services and the variable availability of resources due to the network congestions that characterize a non-dedicated network environment. The structural properties of the optimal solutions are studied and considered as the basis for the formulation of heuristics that perform close to the optimal policy.