Modeling of QoS-oriented content delivery networks

A content delivery network (CDN) is composed by a set of "reverse proxies" placed in proper geographical locations which provide caching and content distribution services to third party Web sites. Client requests are dispatched to one of the cache nodes that constitute the proxy by using content-aware and state-aware switching. Different distributions are generally believed to be more representative of the general traffic behavior; the classical Markovian model well captures the peculiarities of high intensity traffic during the busiest periods. The Markov chain is finite since, it admits a maximum amount of concurrently processed requests and derive the asymptotic state probabilities of the model of the CDN which can be finally used to configure the CDN with proper parameters to sustain the requested service levels, and thus to meet the SLA for each service class.