Connection availability analysis in communication networks

Connection availability is the probability that a given connection or application in a network is operational at a given time. Connectivity from source to destination is necessary but not sufficient to ensure connection availability The network must also contain a path of sufficient capacity from source to destination to support the connection. In case of link failure, connections on the failed link are disrupted and must be rerouted. In this situation, the routing algorithm looks for spare capacity along alternate paths in the network. High-priority connections can preempt low-priority connections. The disrupted connection is rerouted successfully if there exists an alternate path with spare capacity and if the connection is not bumped by another higher-priority connection. In this paper, we develop a state-enumeration algorithm to compute connection availability and analyse the number of network states which must be evaluated in order to achieve a desired accuracy in the solution.