Modeling High Availability

Carrier grade high availability platforms are designed to enable the development and deployment of highly available services in the telecommunications industry. In order to build-in high availability and compare availabilities that differ in the sixth decimal place during the design phase, fairly detailed stochastic models are needed to evaluate the design and perform design tradeoffs. This paper describes an availability model for a high availability platform using three-level hierarchical decomposition that mixes reliability block diagrams and Markov chains. The model is built and evaluated using the SHARPS software package. Sensitivity analysis is performed to identify the effects of critical parameters