Safety-critical Wide Area Network Performance Evaluation

There has been a considerable amount of research in the area of network performance evaluation. However, little of the research is focused on the evaluation of real-time safety-critical WANs, a need that motivated this research. Over the years, networks have been evaluated by different disciplines from different perspectives. Many of these evaluations focus on network technical performance, or an organization's performance when using a network, or individual users' performance when using a network. In this study, network performance was measured using empirical data from an operational WAN and by utilizing well-defined and well-known network performance metrics such as reliability, availability, and response time. In general, increased use of a real-time WAN in this study was associated with negative impacts on WAN performance and increased redundancy was generally associated with positive impacts, allowing greater system usage and higher network workload, as intended. The impacts of increasing redundancy on MTBF were mixed, as were the MTTR impacts; availability values varied considerably by port. The network performance data thus shows mixed empirical results from increases in network usage and redundancy, which highlights the importance of managing and measuring network performance at both the system and the local level.