The document discusses the strategy of "Defense in Depth" for increasing the robustness of biomanufacturing systems. It involves introducing redundancy to mitigate the impact of failures and ensure the system can tolerate variability and failures. The Bioproduction Group advocates using their modeling and simulation software to quantitatively evaluate different sources of variability and analyze how increased redundancy through approaches like scheduling flexibility and additional equipment can improve robustness. A case study example from Genentech showed how robustness analysis allowed optimizing existing equipment usage over installing new equipment.