A double-event testing approach to improve network-element availability

To meet the demand for high availability in telecommunications networks, it is necessary to ensure sufficient availability of the elements that compose the network, e.g. switching systems. Two attributes key to a network element's availability are reliability and maintainability. Reliability is the element's ability to detect faults and perform automatic actions to minimize the occurrence and impact of service outages. Maintainability is the element's ability to help maintenance personnel perform repair actions quickly and with a minimal risk of outage inducing error. This paper presents an extension of the existing approach to: (1) systematically consider double-event scenarios; and (2) include events other than hardware faults. In the proposed approach, an event could be a hardware fault, a procedural error, a system initiated or manually initiated maintenance activity. An example of double-event scenario is a hardware fault occurring during an automatic reload which was caused by a procedural error.