Track 2 Session 12
1:00 to 2:00 p.m. Thursday June 11, 2009

Integrated Hardware, Software and Procedures System Availability Model

As converged communication systems become increasingly feature rich, interactions involving application, control and hardware layers also grow in complexity. Customers increasingly expect very high availability, which is driven by reliability requirements, modeling and analyses that take a comprehensive view of hardware, software and procedures. In previous approaches to predicting system availability, hardware and software have typically been modeled independently; procedures have frequently not been modeled. We developed an integrated availability model that accounts for the effect of hardware, software and procedures, as well as their interactions. We applied this model to an optical transmission system. We added software and procedure elements representing system failures during planned maintenance actions. The model yields downtime predictions that are in reasonable agreement with estimates from field data. This approach is superior to separately modeling hardware, software and procedures failures because it captures interactions among root causes and offers a holistic view of system availability from the customer’s perspective.