A simplified availability modeling tool for networks with 1:1 redundant software-hardware systems

This paper proposes a simplified availability modeling worksheet (SAMOW), a computational tool that incorporates Markov analysis and reliability block diagram methodologies to model and analyze the availability of a typical end-to-end solution consisting of multiple complex component systems, where the failure of each component system is attributed to software failures and hardware failures. The application of SAMOW to 1:1 system redundancy, which is common in the networking industry, is the focus of this study. The end-to-end availability is modeled and computed based on the corresponding signaling path and bearer path since the paths can transverse through different component systems. It is observed that SAMOW is very accurate (compared with the Markov model) when applied to 1:1 redundant systems under various system parameter sets with high switchover coverage.