Probabilistic model for quality of service modelling in packet-switched data networks

A probabilistic model for quality of service available to users for communication via packet-switched public data networks is presented. The concepts of network reliability, availability and congestion are discussed. It is shown that network congestion appears as a loss of availability with regard to data communication services provided to network users, and therefore the quality of service depends not only on equipment reliability and maintenance activity, but also on the congestion probability. After defining the network equivalent availability, a probabilistic model for its evaluation is presented. New concepts are introduced for network equivalent availability evaluation; they consider network component reliability, their maintainability, and the network congestion together