Reliability and availability of a wide area network-based education system

An important class of quality of service (QoS)-dependent network-based applications are computer-based education systems. A successful network-based education (NBE) system needs to provide appropriate QoS at the user level. This includes adequate end-to-end response delay and adequate system reliability and availability. This paper presents results from a reliability and availability evaluation of NovaNET. NovaNET is a successful low-overhead multimedia education system which serves thousands of users on a daily basis. We analyze eight years of failure data and examine correlations among system failure events. The NovaNET data are used to discuss practical bounds on the reliability and availability of an NBE system.