Equivalence of Performance
An equivalence of realised performance across operational nodes is a highly important factor with respect to large-scale systems, indeed for any system. In this chapter, we explain equivalence of performance and why it is so important. We also explain how it is never achieved within the majority of deployed systems. This additionally leads us into a discussion of equivalence of process across both operational nodes and, where applicable, between systems. We then consider the importance of equivalence of performance from the system operator’s perspective, including the visibility of errors and the balancing of error rates against perceived risk. The potential for denial of service and perceived discrimination is discussed, as well as the potential for fraud within a system that has no integral equivalence of performance management and reporting. The APEX concept and system is introduced as an example of how equivalence of performance may be addressed. The APEX architecture is discussed and overviews are given of the APEX Node software and the APEX Device Simulator and how they may usefully be utilised. The APEX Host software is discussed in some detail, including the directory of nodes, transaction monitoring, real-time alerts generation, the generation of reports and how the host software provides for a complete view of the entire system, whether it consists of a collection of nodes at one operational location, several nodes at several locations within a national context, or multiple nodes at multiple locations within an international context. APEX is the only system to date which provides such functionality. From here we discuss the management of equivalence of performance, including the setting of the performance criterion in relation to the perceived level of risk and how this may be dynamically controlled. We also discuss security factors, systems integration and possible next steps for developing and implementing an equivalence of realised performance functionality for large-scale systems. As such, this is a very important chapter as attention to these issues may provide a very significant operational improvement for relevant systems, in addition to the potential for equally significant cost savings with respect to support and maintenance.