Calculating network availability

Network availability is defined as the fraction of time that a network is able to provide communications services and is one of the most important performance metrics for both space and terrestrial networks. In this paper, a general methodology for defining network availability metrics is presented along with analytical and computational methods for calculating these metrics. A series of simulation studies have been conducted utilizing these new definitions and methods. Results show that the computational approaches for various availability metrics can closely approximate those calculated by analysis and be applied to a wide range of network topologies.